According to a motor rotational angle detection device which includes a plurality of motor rotational angle detection units which detect a rotational angle of a motor, and a normal angle decision device which includes a motor rotational angle information item and decides a normal motor rotational angle, in which when a difference is caused between output values of the plurality of motor rotational angle detection units, the normal angle decision device respectively compares the output value of each of the motor rotational angle detection units with the motor rotational angle information item included in the normal angle decision device, and identifies the normal motor rotational angle detection unit, and decides the normal motor rotational angle.