An image position detector includes a light emitting element to emit light to an image on an image carrier, a first light receiving element to receive a specular reflection of light from a surface of the image carrier and output a first light receiving signal, and a second light receiving element to receive a diffuse reflection of light from a surface of the image and output a second light receiving signal. The image position detector is configured to find the end position of the image according to a multiplied value obtained by multiplying values of the first and second light receiving signals by a constant coefficient.