A man seen acting suspiciously in Park Road, Blackpool, was found to have three knives in his jacket.
Dean Harvey, 39, of Egerton Road, North Shore, pleaded guilty to three offences of possessing a blade in public.
Pam Smith, prosecuting, said police saw Harvey behaving furtively on October 18 at 2.40pm.
David Charnley, defending, said Harvey, who has a limited mental capacity, forgot he had the knives. Harvey was bailed for pre-sentence reports by Blackpool magistrates.