Sean Heaps, 31, of The Fieldings on Huthwaite Road, Sutton, appeared before the court in Mansfield and admitted a charge of possessing a small amount of the class B drug.
Accompanied by a care worker in court, the magistrates were told that a member of staff had found the drug on Heaps.
He had a previous conviction of cannabis possession dating back to 2012.
Defending himself, he said he had nothing to say when asked to explain his actions.
He was fined £50, made to pay £180 criminal courts charge, £50 court costs and a £20 surcharge.