PURPOSE: To reduce power consumption of a storage device by providing a device for detecting access frequency of a magnetic valve storage device, by stopping a rotating magnetic field action of the magnetic valve and by stopping an electron circuit power supply.

CONSTITUTION: An access request from a controller to a magnetic valve module 8 is monitored by an access frequency detection circuit 10, and when there is no access request for a specific time storage, a power source activation disconnection circuit 11 is actuated and the power supply of a storage power source 12 is discontinued. When there is any access request for the storage device at the time of power source disconnection, the circuit 11 is activated by the circuit 10 to supply the power source to the storage device. After an initial setting circuit 9 initially sets the respective circuits by the power supply, the storage device makes a normal action.