The First Minister announced the change at the SNP spring conference in Aberdeen, saying it meant four of his 10-member top team would be women.
His speech was the climax of a relatively short, but emotionally charged meeting for the party, as it gathered for the last time before the historic vote on September 18.
Salmond said he wanted companies in an independent Scotland to aspire to having their boards be 40% female.
He said: "We practice what we preach. The Cabinet is our board as a country, and women will make up 40% of the members of the Scottish Cabinet."
The Cabinet changes were announced shortly after Deputy First Minister Nicola Sturgeon told foreign media that the SNP had plans to close the "gender gap" in the referendum.
Opinion polls show support for a Yes around 10 points lower among women than men.
Shona Robison, currently Minister for Equality, Sport and the Commonwealth Games, will now serve at Cabinet Secretary level with additional responsibility for pensioners' rights.
Angela Constance, currently Minister for Youth Employment, will take the brief into the Cabinet with responsibility for implementing the Wood Commission on helping young people into work.
Their salaries will rise from £85,445 to £101,757.
However, unlike other Cabinet members, they will not be supported by a team of their own ministers.
A spokesman for Salmond dismissed suggestions the promotions were tokenism, but acknowledged they were intended to send a wider message to the electorate.
Scottish Labour's shadow cabinet is already 40% female.
Amid rising support in the polls, previous SNP caution was set aside, with ministers and delegates confidently predicting a Yes win. Some SNP ministers now believe a 60%-40% victory is likely.
However, the high stakes - and the knowledge that a No would be crushing for the SNP - also led to a lack of debate and the avoidance of any controversy.
Salmond stuck to familiar ground, demanding David Cameron debate with him on TV, gave a "cast-iron guarantee" that Trident would be expelled and the bedroom tax abolished after a Yes vote, and attacked the Westminster establishment for talking down Scotland.
His words received a thunderous response from around 1000 delegates in Aberdeen's Exhibition and Conference Centre, which boomed with regular outbreaks of mass foot-stamping.
The half-hour speech received a five-minute standing ovation.
The First Minister said momentum was firmly with the Yes side, as the No campaign actively repelled voters with scare stories. He said: "The more the people of Scotland hear the case for No, the more likely they are to vote Yes.
"They are the most miserable, negative, depressing and thoroughly boring campaign in modern political history.
"They are already out of touch with the people and are now losing touch with reality."
Salmond also had a message for the so-called Cybernats and others in the Yes camp accused of bullying and intimidating unionists. He said: "The Yes campaign is positive, uplifting, hopeful and must always stay that way."
He stressed the vote was not about the SNP or him personally, or even the wider Yes campaign. "It's about putting Scotland's future in Scotland's hands," he said. "It's a vote for a government in Scotland that the people of Scotland choose.
"A government in control of tax, the economy, social security, employment, immigration, oil and gas revenues, European policy and a range of other areas currently under Westminster control.
"That may be the SNP. It may be Labour. It may be a coalition. I tell you what it won't be. It won't be a government led by a party with a single MP in Scotland. A government dismantling our welfare state, privatising public services.
"In an independent Scotland we can give this guarantee: the era of Tory governments unelected by the people of Scotland handing out punishment to the poor and the disabled will be gone and gone for good."
The lure of a Tory-free Scotland was one of many comments aimed at Labour supporters, around one-quarter of whom already intend to vote Yes.
In one of the most forceful passages in his speech, Salmond said Scotland had the resources, people and talent to be a wealthy nation and now had to choose its future direction.
One future, under Westminster, held growing child poverty, foodbanks and a detached super-rich elite. In contrast, independence would see Scotland take responsibility for creating a more equal nation with a sense of "shared national mission".
He also promised an expanded childcare system which would be "the envy of the world", helping the poorest children and letting more women return to work.
He ended his speech by looking ahead to Scotland joining "the international family of nations" in March 2016 after a Yes vote.
"Let's keep the eyes of the world on Scotland," he said. "Let us build a nation that carries itself with pride and humility in equal measure … which yields to no-one in ambition, and that, come independence day, walks tall among the nations of the Earth - on that day, and on every day thereafter.
"This is our moment to be a beacon of hope, a land of achievement.
"Our country, our Scotland, our independence."
Professor John Curtice of Strathclyde University's politics department said the SNP's overt appeals to women voters were based on a misunderstanding.
He said: "It's not about childcare or the glass ceiling. Women are more pessimistic than men about the economy and more uncertain about what independence would bring - and there wasn't much in the speech about the economy.
"Closing the gender gap is going to be impossible [for Yes]. If they're going to win they will just have to win among men."
Shadow Scottish Secretary Margaret Curran called Salmond's speech "drivel", adding: "Women will see through his cynical attempts to win them over."
Conservative MSP John Lamont said: "Alex Salmond knows he has a problem appealing to half of the electorate, but women can spot a dodgy chat-up line when they hear it. He has had seven years to do something about childcare, but he is only now interested in the issue because he thinks there are votes in it for himself."
Former Liberal Democrat leader Sir Menzies Campbell said the speech failed to answer the "big questions" hanging over independence.