A cutter includes a handle, a cassette and a sliding element. The handle includes a slot in an end and two grooves in two opposite internal faces. The cassette includes two bosses and a catch. The bosses are inserted in the grooves to allow the cassette to translate and pivot. The catch is formed on the cassette. The sliding element includes a fin, and is movable in the handle between a rear position and a front position. In the rear position, the fin is separated from the catch and the cassette is far from the slot. In the front position, the fin is in contact with the catch and the cassette is located near the slot. The catch is abutted against the fin so that the cassette is moved forward in the handle while the sliding element is moved to the front position from the rear position.