To dissolve the nonconformity of a conventional actuator referring to such a problem that it causes the leakage of a magnetic field from the side and a problem that it can not operate stably in the whole movable range.

This magnetic actuator is equipped with a first magnet array where magnets 10a to 10d are arranged side by side with their different magnetic poles directed alternately and plane coils 12a and 12d which are installed astride the two or more magnetic poles of the first magnet array, and this gets driving force by letting a current flow to the plane coils 12a to 12d. The problems are solved by using this magnetic actuator where magnets 24a and 24d are arranged at a specified interval from the first magnet array, thereby forming a second magnet array, and the second magnet array is constituted by juxtaposing the magnets 24a to 24d with mutually different magnetic poles facing the magnetic poles of the magnets 10a to 10d of the first magnet array.