A chuck (4) for grasping a writing lead and a rotor (6) arranged to be movable in a direction of rotation and an axial direction within a body cylinder (1) are provided. A rotational drive mechanism for the writing lead is formed such that first and second cam faces (6a) and (6b) are respectively formed at one end face and another end face of the rotor in the axial direction, and first and second fixed cam faces (13a) and (14a) are arranged on the body cylinder side to face the above-mentioned first and second cam faces respectively. A pipe end (7) for guiding the writing lead to interlock with retreat and forward movement of the writing lead while the writing proceeds is arranged to move in the same direction, in conjunction with retreat and forward movement of the above-mentioned chuck.By this structure, a mechanical pencil is provided in which the above-mentioned writing lead is gradually rotated using the retreat and forward movement of the writing lead by way of writing pressure, and which can keep constant a protrusion length of the writing lead protruding from the pipe end when writing.