A control device includes a standard substrate on which a first input/output circuit and a control circuit configured to control the first input/output circuit are mounted, and a power supply substrate on which a connection portion and a power supply circuit are mounted. The first input/output circuit is at least one of an input circuit or an output circuit for a standard electrical equipment. The connection portion is configured to be connected to a power supply line for supplying electric power. The power supply circuit is configured to generate electric power for operating the standard substrate from the electric power supplied from the power supply line.