A disk drive includes a casing having a mount surface. The casing houses a disk-shaped recording medium, a drive motor which supports and rotates the recording medium, a head which performs information processing for the recording medium, a head actuator configured to movably support the head and move the head relative to the recording medium. A control circuit board is arranged to overlap the mount surface of the casing. A holding seal is adhered to the control circuit board and the casing, covering a peripheral portion of the control circuit board to press the peripheral portion to the mount surface.