PURPOSE: To provide a magnetostrictive actuator capable of generating complex deformation and displacement as well as with a small and simple structure as an actuator.

CONSTITUTION: A magnetostrictive actuator includes a magnetic material 9 having magnetostrictive force and a coil 10 for applying a magnetic field to the magnetic material 9. The coil 10 is formed in a magnetic material 9 in a body. A plurality of magnetic field generating means (magnetic circuit or permanent magnet) are provided around or within the magnetic material 9. Consequently, a complex displacement can be obtained through the magnetic material 9 that is put in a complex bias magnetic field and a control magnetic field by positioning the magnetic-field generating means adequately and adjusting the magnetic field in a desired direction.