The brewery will sell 2% of its share capital with a minimum investment of £10, The Morning Advertiser (MA) understands.
The campaign, called AdventureCapital, comes as part of a wider push from the brewer to double its current turnover, which is £12.5m, to £25m over the next three years.
Innis & Gunn founder Dougal Gunn Sharp said: "We've never made shares available before and I couldn't think of anyone better to offer them to than the people who want to help us discover where we can take the beer of tomorrow."
The brewer plans to open four more Beer Kitchen (its bar and restaurant concept) sites as well as expanding beer production at the recently acquired Inveralmond brewery in Perth and installing a barrel-ageing hall and new filtration technology.
Innis & Gunn bought the Inveralmond brewery last year with £3.1m raised via its BeerBond programme, which offered investors a four-year, initial fixed-term mini bond with an interest rate of 7.25% gross interest per annum for investments from £500.
The brewer also announced, this morning, the launch of new beer Sky.P.A, which uses water from clouds above the Scottish Highlands "harvested" with a specially developed moisture collecting machine.
A four-person team flew the device over Devil's Beef Tub in Moffat, Scotland, collecting enough cloud water to brew 500 pints of the beer.
Sharp added: “Beer drinkers are becoming more discerning about what they drink and insipid, mass-produced beers are losing favour with a broad base of consumers who are looking for more diverse and unique flavours.
“Despite this, craft beer still accounts for a small fraction of the beer consumed annually – this means we have substantial opportunities for growth.”
Innis & Gunn is the latest of several craft brewers to turn to crowdfunding this year. Sussex-based Bedlam Brewery launched a crowdfunding campaign in September, smashing its target of £330,000 by more than £130,000.