Mechanical pencil

A mechanical pencil comprising

• a ball chuck allowing advance of lead and preventing retraction,
• a rotation drive mechanism having a rotary part and receiving a retracting motion in the axial direction due to writing pressure received by the lead gripped by the ball chuck and an advancing motion in the axial direction due to release of writing pressure so as to make the rotary part be driven to rotate in one direction,
• a feedout face having a ring-shaped cam face and a drop difference in the axial direction provided at the ring-shaped cam face,
• an input member rotating upon receiving a rotational drive force of the rotary part, and
• an output member having an abutting part abutting against the feedout face and a slider provided with a holding chuck holding lead,
• configured so that the abutting part moves along the feedout face corresponding to rotation of the output member and so that advancing motion of the slider when the abutting part drops into the drop difference causes lead held by the holding chuck to be pulled out by the ball chuck, and
• further comprising a clutch mechanism transmitting rotational movement of the input member to the output member so that when the input member rotates by exactly a first rotational angle, the output member rotates by exactly a second rotational angle smaller than the first rotational angle.