A magnetic actuator, comprising a magnet, mutually opposite magnetic poles thereof being arranged opposing each other, and a coil, at least one portion thereof being inserted between the corresponding magnetic poles, wherein a driving force for the coil is generated by applying an electric current to the coil in a magnetic field generated by the magnet. Acceleration is traded off in favor of higher velocity upon detecting a tape storage drive is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. A PMOS transistor is formed on a second region of a semiconductor substrate.