Jackson Carlaw, the Scots Tory deputy leader, accused ministers of taking a "travelling circus" to the US.
The First Minister led the trip to the Europe versus US golf tournament at Medinah, near Chicago, in September.
The delegation – officially dubbed "Team Scotland" – also included Sports Minister Shona Robison, 12 Scottish Government officials and a further 22 officials from VisitScotland and other quangos. In addition, representatives from Gleneagles Hotel, Perth & Kinross Council and Tayside Police attended the tournament.
The First Minister took part in the closing ceremony, receiving a silver putter to mark Scotland taking over as Ryder Cup host. The tournament will be played at Gleneagles in 2014.
Other engagements during his five-day stay included the launch of Airdrie-based potato firm Albert Bartlett's Rooster brand in the US.
He also delivered a speech to business leaders at the Chicago Council on Global Affairs and attended a concert linked to the Celtic Connections music festival. Full details of the trip were provided in a parliamentary answer yesterday by Culture Secretary Fiona Hyslop.
She said: "The Team Scotland approach in Chicago will help ensure we maximise the economic benefits of hosting the Ryder Cup in 2014, which will generate at least £100 million."
The bill for the trip was £468,580, though Ms Hyslop insisted "every effort was made to minimise costs".
Mr Carlaw said: "I am generally accepting of the First Minister's US trip, given that Scotland will host the next Ryder Cup. However, like most taxpayers, I am astonished that the costs incurred bear more relation to a head of state with a travelling circus than to the more modest expense which would have been appropriate and justifiable."
Scottish Liberal Democrat leader Willie Rennie MSP said: "When money is tight, spending half a million pounds on a trip to the USA has to be questioned for value for money."
Labour MSP Patricia Ferguson said: "To find out that Alex Salmond's trip to watch the golf cost all of us almost half a million pounds is eye-watering.
"This comes on top of the tens of thousands of pounds spent on his trip to the opening of Brave in California."
A spokesman for the First Minister said: "This is breathtaking hypocrisy from Labour. They spent more than this on Tartan Day trips to the US during each of their last three years in office."