According to one embodiment, a spring assembly includes: a substrate; a coil spring having an end turn portion fixed to the substrate; an inner wall provided at an inner peripheral side of the coil spring; and an outer wall provided at an outer peripheral side of the coil spring, wherein one of the inner wall and the outer wall forms a spring fixing wall configured to prevent the end turn portion of the coil spring from coming off in an axial direction of the coil spring, and wherein the other of the inner wall and the outer wall forms a support wall configured to prevent the end turn portion of the coil spring from moving in a radial direction of the coil spring.