ENCODER AND MOTOR INCLUDING THE SAME

An optical module is stably held. The disclosed encoder is provided with: a rotating plate that rotates about a rotating shaft; an optical module (22) including at least one of a light source that irradiates the rotating plate with light and a light receiving element that receives light reflected by the rotating plate or light transmitted through the rotating plate; a substrate (23) on which the optical module (22) is disposed; and a frame that supports the substrate. The substrate (23) has a first mounting hole (23a) and a second mounting hole (23b), and is screwed to the frame by a first screw inserted into the first mounting hole (23a) and a second screw inserted into the second mounting hole (23b). The optical module (22) is disposed on a first line segment (L1) connecting the center of the first mounting hole (23a) and the center of the second mounting hole (23b) when viewed from a direction along the rotation axis. 稳定地保持光学模块。所公开的编码器具备：旋转板，其以旋转轴为中心旋转；光学模块(22)，其包含对旋转板照射光的光源和接受由旋转板反射的光或透射旋转板的光的受光元件的至少一方；基板