Charity Corby Mind runs drop-in sessions for people in mental distress but only the group's Crisis Cafe is NHS funded.
Money raised will go to fund counselling support staff for their peer-to-peer group and the weekly debt management course.
Morgan Hay, fundraising lead for Corby Mind, said: "Our Christmas fair gets our message out there to people.
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"We are really busy and there's so many different areas of mental health - post natal depression, addiction, if you haven't got that support we want to be here for you.
"We see Corby Mind as a hub for mental health. We have the Crisis Cafe and a drop-in for 11 to 25 year olds run by Youth Works.
"One of the hardest things is to come through our door but we are here to help to fill in any forms, make you a cuppa and we are non-judgmental."
Corby Mind's Christmas fair takes place at East Carlton Park from 12 noon to 3pm on Sunday, December 1.
There will be music from Gretton Silver Band, and , and performances from Cottingham and Middleton community choir Valley Voice, and Corby's Chordless Community Choir.
Santa will be in his grotto and tickets will be on sale in the log cabin from 11.30am costing £4 per child with tickets available on a first come, first served basis.