An image forming apparatus includes an external gear to which a rotating force of a resist gear is transmitted, a ratchet for transmitting a rotating force from the external gear to a paper feed roller or releasing the transmission, and a ratchet arm having a claw engaged with the ratchet to transmit a rotation of the external gear, thereby rotating the paper feed roller, and a claw engaged with a slit provided on a boss of the paper feed roller to turn the paper feed roller toward a rotation start position and removing the claw from the ratchet to stop the paper feed roller, and the boss is provided with an offset bottom peripheral surface to be moved with the claw entering to stop the rotation of the paper feed roller when a resist sensor detects a tip of a recording paper.