To provide a power supply failure detection method which comprises a simple power supply failure detection/recording means by using software, to record necessary information without depending on an auxiliary power supply, and without requiring special hardware, and to provide a medical apparatus mounted with the function of the method.

The power supply failure detection method comprises a non-volatile memory which records the operation time information of a device, confirms a normal operation state at each prescribed time, updates an operation confirmation time, and records the final operation confirmation time in a power-failure operation recording region when an operating identifier is detected as an operation history flag at the start of an operation.