Provided is a motor assembly including a supporting body; a bearing member including an inner race and an outer race; and a supporting unit for supporting the bearing member onto the supporting body, wherein the supporting body comprises: a receiving portion with an opening on a portion in the diameter direction of the output shaft for receiving the bearing member having a first supporting surface disposed perpendicularly to the output shaft of the motor and a second supporting surface separated from the first supporting surface in parallel to the first supporting surface; a side surface of the outer race of the bearing member contacts the first supporting surface, the supporting unit includes a bearing sheet that is forcedly inserted between the other side surface of the outer race in the bearing member that is received in the receiving portion and the second supporting surface, wherein the bearing sheet includes a radial supporting portion contacting an outer circumferential surface of the bearing member received in the receiving portion so as to prevent the bearing member from escaping from the receiving portion.