According to one embodiment, a disk device includes a case having a bottom wall, a disk-shaped recording medium located in the case, a drive motor which is located in the case and supports and rotates the recording medium, a head which performs information processing for the recording medium, a head actuator, and an inertial latch mechanism which latches and holds the head actuator in a retracted position when an external force is subjected. The inertial latch mechanism is modularized and includes a base plate, a first pivot and a second pivot set up on the base plate, a latch arm supported for rocking motion around the first pivot, an inertial arm which is rockably supported on the second pivot, and a stopper portion which prevents the latch arm and the inertial arm from slipping off the first and second pivots.