The invention provides a robot and a gear device that can achieve an extension of the life of the gear device. The gear device is characterized in that the gear device includes an internal gear, an external gear having flexibility configured to partially mesh with the internal gear and relatively rotate around a rotation axis with respect to the internal gear, and a wave generator configured to come into contact with an inner circumferential surface of the external gear and move a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis. The wave generator includes a cam having a noncircular outer circumferential surface and a bearing disposed between the inner circumferential surface of the external gear and the outer circumferential surface of the cam. The bearing is an angular ball bearing.