In a wire dot printer head of the present invention, an armature is formed by coupling a magnetic circuit formation member having a supported piece with one end inserted into a cavity formed on a surface of a yoke to an arm coupled to a wire. The supported piece of the armature is rotatably supported by a support point, thereby a side surface of the cavity and a side surface of the supported piece, and a bottom surface of the cavity and an end surface of the supported piece can be set in the proximity. Accordingly, magnetic resistance between the magnetic circuit formation member and the yoke can be reduced.