A light source is suppressed from being reflected on a workpiece surface of a specular workpiece. A code reading device generates a code image by receiving light specularly reflected from a specular workpiece surface of light emitted from a diffuser and diffusing and reflecting light emitted to a portion corresponding to a code. A position and an angle of the diffuser are fixed with respect to a camera such that the specularly reflected light from the workpiece surface is received by the camera in a state where the camera is in focus on the workpiece surface, and the light source emits the light from the back of a rear end of the diffuser toward the diffuser such that the light source is not reflected on the camera when the camera receives the specularly reflected light.