A protrusion is opposed to a head actuator positioned at the inoperative position in a recording medium drive such as a hard disk drive. When a larger impact is applied to the head actuator, the head actuator deforms by a predetermined amount, so that the protrusion receives the head actuator. The deformation of the head actuator is thus restricted. A collision can be avoided between the head actuator and the recording medium. The predetermined amount can be determined based on the space or distance between the head actuator and the recording medium. It is possibly easy to assemble and position the protrusion relative to the head actuator at a higher accuracy, as compared with the case where the overall planar surface must be positioned relative to the head actuator at a higher accuracy in the conventional manner. This leads to the production of the protrusion or displacement suppression member at a lower cost.