The disclosure provides a structure for suppressing occurrence of dew condensation on a cover member in an image sensor for industrial use. An image sensor includes an illumination part for illuminating a subject, a lens part for forming an optical image of the subject, an imaging part for generating an image based on the optical image, and a housing for accommodating the illumination part, the lens part, and the imaging part. A light-transmissive cover member covering a front side of the lens part and the illumination part is attached to the housing. A wall member partitioning a space where the lens part is arranged and a space where the illumination part is arranged is provided inside the housing, and the housing has a heat transfer structure for transferring heat generated inside the housing to the cover member.