Abstract: A deep groove ball bearing includes an outer ring, an inner ring, a plurality of balls, and a seal member. An axial cross-sectional width is smaller than a radial cross-sectional height, a thickness of the inner ring is greater than a thickness of the outer ring, and a pitch diameter of the ball is larger than a median diameter between an inner diameter of the inner ring and an outer diameter of the outer ring A radial dimension between an outer diameter of a shoulder portion of the inner ring and an inner diameter of the seal member is greater than the thickness of the outer ring. As a result, width and weight can be reduced, a load capacity can be secured, grease leakage can be prevented, and a service lifespan can be extended.