In an apparatus for optically reading a target based on light reflected from the target, an imaging lens with a first optical axis is provided so that the reflected light enters into the imaging lens. A photodetector having an active area and a second optical axis different from the first optical axis is provided. The imaging lens focuses the reflected light on the active area of the photodetector. A fold mechanism is arranged between the imaging lens and the photodetector. The fold mechanism folds an optical path of the reflected light between the imaging lens and the photodetector to adjust a length of the optical path while keeping each of the first and second optical axes constant.