A semiconductor device includes a control section, a first arm, and a second arm; and has an H-bridge circuit to supply an input current supplied from a power source to an output terminal as a reversible electric current on the basis of a control signal outputted from the control section and a reverse-connection-time backflow prevention circuit to prevent an electric current in a direction opposite to the direction of the input current from being supplied to the H-bridge circuit. The first arm is formed over a first island. The second arm is formed over a second island. The control section and the reverse-connection-time backflow prevention circuit are formed over a third island.