A motor control device avoids the difficulties associated with safely controlling a motor using a second calculation unit when a first calculation unit malfunctions. A motor control device monitors a malfunction of a first microcomputer and a malfunction of a first CPU of the first microcomputer and performs a determination based on a result of a second external communication functional unit. When the determination is normal, the process proceeds determine that the first CPU is normal and a second CPU malfunctions. Therefore, it is possible to continue processing using the first CPU in this case.