A computer device includes a power supply unit which includes an instantaneous power failure resistance capacitor and converts an alternating current into a direct current and outputs the direct current, and a main body which includes a main storage unit having a non-volatile storage area and a processor for executing programs, wherein the power supply unit includes a power failure detection unit which detects that a supply of the alternating current has been stopped, and wherein the main body includes a logical device which, when the detection is notified from the power failure detection unit, instructs the processor within a retention time of the instantaneous power failure resistance capacitor to perform transaction processing of converting data of a buffer in the processor into reusable data and transferring the reusable data to the main storage unit.