A motor connectable to a load and comprising at least: a frame in a shape of a bottomed cylinder with an open end; a stator housed in and fixed to the frame ; a rotor facing the stator at a predetermined distance; an end plate above an opening of the frame , the end plate being a resin plate member covering the opening and having, at a center thereof, a through-hole penetrated by a rotary shaft ; and a bearing closing the through-hole of the end plate and rotatably supporting the rotary shaft , the end plate having, on an outer periphery of an outer surface thereof, a step with a side surface radially facing an inner circumferential surface of the frame , the motor further comprising an annular housing space (S) defined between the side surface of the step and the circumferential surface of the frame , the annular housing space (S) housing a seal ring that is an annular elastic body, and the step having a bottom with a part extending to a radially outer edge of the outer surface of the end plate and inclined radially outward toward a bottom of the frame , the bottom of the step includes: a first bottom at a radially outer end thereof; and at a radially inner end thereof, a second bottom continuous with the first bottom , and the first bottom extends to the radially outer edge of the outer surface of the end plate , and is inclined radially outward toward the bottom of the frame, whereas the second bottom is inclined in a direction axially different from the first bottom , wherein, before the assembly of the load and the motor, an axial protrusion (A) of the seal ring above the frame is longer than the axial height (B) of the first bottom with respect to the second bottom , and wherein, at the assembly of the motor and the load , a pressure is applied from the load onto the end plate in the axial direction, such that the seal ring is pressed from a surface of the load toward the bottom of the frame . a frame in a shape of a bottomed cylinder with an open end; a stator housed in and fixed to the frame ; a rotor facing the stator at a predetermined distance; an end plate above an opening of the frame , the end plate being a resin plate member covering the opening and having, at a center thereof, a through-hole penetrated by a rotary shaft ; and a bearing closing the through-hole of the end plate and rotatably supporting the rotary shaft , the end plate having, on an outer periphery of an outer surface thereof, a step with a side surface radially facing an inner circumferential surface of the frame , the motor further comprising an annular housing space (S) defined between the side surface of the step and the circumferential surface of the frame , the annular housing space (S) housing a seal ring that is an annular elastic body, and the step having a bottom with a part extending to a radially outer edge of the outer surface of the end plate and inclined radially outward toward a bottom of the frame , the bottom of the step includes: a first bottom at a radially outer end thereof; and at a radially inner end thereof, a second bottom continuous with the first bottom , and a first bottom at a radially outer end thereof; and at a radially inner end thereof, a second bottom continuous with the first bottom , and the first bottom extends to the radially outer edge of the outer surface of the end plate , and is inclined radially outward toward the bottom of the frame, whereas the second bottom is inclined in a direction axially different from the first bottom , wherein, before the assembly of the load and the motor, an axial protrusion (A) of the seal ring above the frame is longer than the axial height (B) of the first bottom with respect to the second bottom , and wherein, at the assembly of the motor and the load , a pressure is applied from the load onto the end plate in the axial direction, such that the seal ring is pressed from a surface of the load toward the bottom of the frame . <EOS>