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.