An information processing device comprises a plurality of processing units on which OSs and execution environments operate, and shared peripheral devices shared by the plurality of processing units. The information processing device is provided with a failure concealing device for concealing a failure which has occurred in a processing unit. The failure concealing device determines a substitutional processing unit that will act as a substitute for a failed processing unit so that the OS and execution environment which have operated on the failed processing unit will operate on the substitutional processing unit, switches the OS and execution environment which have operated on the failed processing unit so that they will operate on the substitutional processing unit, and switches a shared resource used by the failed processing unit such that it is available to the substitutional processing unit.