The present invention is an actuator locking mechanism used for an information recording apparatus, having a simple structure and a large securing force. A locking mechanism of the present invention comprises an actuator, an attractable member, a support member, a spring, and an inertia member. While the attractable member and the actuator are attracted to each other, the support member rotates correspondingly to the movement of the actuator due to an impact force applied to an information recording apparatus, the spring provides elasticity for the support member while elastically deforming, moreover the inertia member is rotated by the impact force, and a securing portion of the inertia member contacts the actuator to limit the movement of the actuator due to the impact force.