To facilitate failure detection in a dynamic brake circuit.

A motor control device includes a first failure detection circuit that outputs a first monitoring signal, a switch for failure detection, a second failure detection circuit that outputs a second monitoring signal, and a control circuit portion that uses the first monitoring signal and the second monitoring signal as input. The first failure detection circuit and the second failure detection circuit each include a photocoupler. The photocoupler converts a minute failure detection current into a first monitoring signal and a second monitoring signal for failure detection.