A ball socket structure is provided, which includes a ball portion and a socket portion, the ball portion and the socket portion being configured to slide against one another, in which the socket portion includes a sliding surface including a PVD coating layer, the sliding surface of the socket portion is a concave spherical surface, and a value (Ds/Rs) of a ratio between a depth Ds of the sliding surface and a radius of curvature Rs of the sliding surface is from 0.05 to 0.70.