A rotary cutter mechanism includes a rotary blade which is rotatably provided around a shaft center and which includes a first cutting edge portion, a counter blade which is provided to face a locus drawn by the first cutting edge portion of the rotating rotary blade and which includes a second cutting edge portion, and a protruding member which is provided on the edge portion of the rotary blade on the first direction side and which protrudes from the rotary blade toward a rotation direction side, the rotation direction side being a side on which the rotary blade faces the object to be cut in a case where the object to be cut is cut between the first cutting edge portion and the second cutting edge portion.