PURPOSE: To provide an attitude control device having favorable responsiveness by providing a loop containing liquid, and controlling the liquid by a drive means to move along the loop.

CONSTITUTION: This attitude control actuator comprises a tube 10 containing a loop of conductive liquid metal, and the tube 10 has a cross-shaped joint 11 formed flat between poles 12, 13 of an electromagnetic pump 14. This joint 11 sets conductive connection between the liquid metal in the tube 10 and a conductive fluid winding tube 15 wound around a core of the electromagnetic pump 14. A magnetic field is generated by a primary winding 16 between the poles 12, 13 in the joint 11, and a transverse current is generated in the conductive liquid inside the magnetic field. Pressure difference to produce propulsion force is generated by electromagnetic effect at this time. Favorable response time can thus be obtained without limitation or mass or power.