A drop sensor detects a drop of a device. When the drop of the device is detected, a sub CPU allows a counter to count a drop time. When the device drops for a predetermined time or more, the sub CPU controls a regulator so that the regulator forcibly disconnects an electric power to be supplied to a hard disc, and writes a drop occurrence flag into a nonvolatile memory. When the power supply is again turned on, a main CPU allows a display section to display information indicating that the power supply is disconnected due to the drop of the device.