Abstract: A sled motor mounting structure is provided with a sled motor which having a rotation shaft and a lead screw which is mounted on the rotation shaft and is in mesh with a mated gear, the rotation shaft being constructed so as to have a play in its axial direction for enabling a smooth rotation; and a stopper provided in front of the tip of the rotation shaft of the sled motor such that the tip of the rotation shaft comes to abutment thereto when the rotation shaft is displaced toward the tip direction thereof within the play due to the rotation of the lead screw which is in mesh with the mated gear, thereby restricting the tip of the rotation shaft from further movement in the axial direction thereof. The stopper is arranged at a prescribed distance from the tip of the rotation shaft when the rotation shaft is moved to the base end within the play. The prescribed distance is set to be less than the play in the axial direction, for example it lies within the range of 0.02 mm-0.05 mm.