The firm's chief executive Gabe Newell revealed the news to the BBC ahead of the British Academy of Film and Television Arts (Bafta) Games Awards. Valve's online PC games store Steam has already proven highly popular and analysts suggest the console, called Steam Box, could have a big impact.
Mr Newell is being honoured with an Academy Fellowship at the event. He was less forthcoming about whether his firm was actively working on new sequels to its hit science fiction franchises Half Life and Portal.
Portal 2 - a puzzle based game involving a prisoner trying to escape test chambers controlled by a homicidal computer - won best game and two other awards at last year's Baftas.
Valve's Steam platform - which promotes titles by other developers as well as its own - has over 50 million registered accounts with software for the Windows, Mac and Linux operating systems