An information processing apparatus includes active units and a standby unit. In the active units and the standby unit, CPUs and DIMMs are divided into a plurality of logical partitions, which are controlled to be diagnosed respectively by diagnosing units. A scheduling unit periodically diagnoses the CPUs and the DIMMs of the standby unit in each of the partitions in turn. If a fault occurs on the active units side, a switching controlling unit controls a partition not being diagnosed in the standby unit to be embedded in an active unit system of the information processing apparatus. The scheduling unit instructs a diagnosis with a smaller number of diagnosis items as a diagnosis performed at reboot after the standby unit is embedded.