A cutter mechanism has a fixed blade and slidable blade which cooperates with the fixed blade to cut a recording sheet. The fixed blade is biased in a direction away from a base portion by a biasing member. A holder supports the fixed blade away from the base portion to cause a cutting edge of the fixed blade to swing up and down and permit opposite ends of the fixed blade to be pushed down at least in the direction of the base portion. The fixed blade holder has a wall portion positioning the fixed blade in a sliding direction of the slidable blade, a first regulating member that regulates lifting of the fixed blade cutting edge, and a second regulating member that regulates lifting of the fixed blade root portion in a state in which a gap is formed between the base portion and the root portion.