Abstract: In an information processing apparatus and elapsed time measuring method of the present invention, a microcomputer for power supply control measures an elapsed time when the product is in an operating condition, a time when the product is powered off is read from an RTC in a system LSI and written to a storage unit in a BIOS, a time when the product is next powered on is read from the RTC, and a difference between the two times is calculated in order to obtain an elapsed time for when the product is in a non-operating condition. An elapsed time of the product is calculated by adding together two types of elapsed times in the BIOS. This structure enables providing an information processing apparatus and elapsed time measuring method that can accurately measure the elapsed time of the product without being influenced by a user operation.