A vertical motor with a cooling structure for an electrical operation machine is provided. The vertical motor includes a driving shaft, having a rotational axis and arranged along a vertical direction; a rotor, rotating with the driving shaft; a stator, arranged around the rotor; a winding, arranged around the stator; a housing, having a wall portion and a bottom portion and accommodating the driving shaft, the rotor and the stator; and an oil sump, provided on the bottom portion of the housing for accumulating a cooling fluid in a manner that a lower portion of the winding is immersed in the cooling fluid. The oil sump has an inner peripheral side wall, the inner peripheral side wall is vertically arranged with respect to the bottom portion of the housing and positioned at an inner side than the lower portion of the winding.