An electric motor 1 includes a first structure 4 including a magnetic pole row formed by a predetermined plurality of magnetic poles 4a arranged in a predetermined direction, a second structure 3 including an armature row disposed in a manner opposed to the magnetic pole row, for generating moving magnetic fields moving in the predetermined direction between the armature row and the magnetic pole row, and a third structure 5 including a soft magnetic material element row. The third structure disposed such that the soft magnetic material element row is positioned between the magnetic pole row and the armature row. A ratio between the number of the armature magnetic poles, the number of the magnetic poles 4a, and the number of the soft magnetic material elements 5a is set to 1:m:(1+m)/2 (m≠1.0).