The aim of the invention is to obtain a single phase motor with high-efficiency and low-price by ensuring the magnetic circuit at the back of the magnetic core to the stator iron at the same time causing the blanking to be excellent shape, wherein, N grooves which are provided with a plurality of electromagnetic steel plates and are formed by stacking and the N/2 is odd number, one part of the groove are large grooves (4), and the other are stator irons (1) which is composed of small grooves (3) with a radical depth shallower than the big groove (4); a main coiling (6) which is inserted to the inner side of the large groove (4) or the small groove (3) with the concentric winding mode of the single-phase two poles; and the auxiliary coiling (7) which is inserted to the inner side of the large groove (4) or the small groove (3) with the concentric winding mode of the single-phase two poles and is arranged at the position outside 90 degrees of the electric angle relative to the main coiling (6); the auxiliary coiling (7) in the N grooves is arranged at the position outside 90 degrees of the electric angle relative to the main coiling (6) thereby setting the groove with coiling volumesmaller than others to small groove (3) and setting other grooves to large grooves (4).