Figures from business angel body Linc Scotland show an increase from £18.49 million to £21.79m.
Around £15.6m of the funding between January and September came from angels, compared to £12.4m in 2011.
Angels are generally high net worth people or syndicates which invest cash in return for equity in a firm.
Linc Scotland, which represents 19 syndicates, said its members had invested 36% more with the figure going from £7.4m to more than £10m, with public sector investment in the first nine months edging up from £6.12m to £6.17m.
The number of firms receiving backing from Scots angels is at 49, with 15 of those entirely new investments. Deals involving Linc members rose from 54 to 59.
David Grahame, chief executive of Linc Scotland, said: "We are fairly encouraged. Although the absolute number of companies is not huge in the grand scheme of things they are all high potential and we are also glad the guys are getting back into some new stuff.
"Appetite for new investment has edged back up since 2010 which was the low point. The figures demonstrate angels are still prepared to invest if the right opportunity is presented to them."
Mr Grahame said Linc Scotland had added new members since last year and on a like-for-like basis the investment would be broadly flat.
He said: "If you only looked at the same group of members as last year then it is probably steady but we have new people in who got going and got deals done."
The lack of exits in recent years has led to many angels and venture capitalists holding on to some businesses in their portfolios for longer than the usual three to five year period.
Mr Grahame said: "There are more exits under discussion but I cannot say we have had a run of them.
"They are still trickling along but at a lower rate than we would like.
"It will be interesting to see what happens as a result of the American election.
"The buyers of our stuff are big corporate and they don't like uncertainty. They are sitting on piles of money and every time there is a wobble in the markets they sit on their money for a further six months.
"If they felt there was predictability they might come back in as they need to start spending for their future and many of them are astonishingly cash rich."