An object of this invention is to reduce the manufacturing cost by simplifying
a reel rotation detecting mechanism in a video cassette deck. A light emitting
element and a light receiving element are engaged on a main substrate provide under
a deck chassis. On the deck chassis is mounted a light guiding member that includes
a pillar portion extending through the deck chassis and a branch portion extending
sideways from the pillar portion. In order to detect the leading ends and trailing
ends of the magnetic tape, the pillar portion guides the light coming from the
light emitting element into the cassette arranged on the deck. The branch portion,
above the deck chassis, guides one portion of the light incident to the pillar
portion to the reel on the deck chassis. The rotation of the reel is detected by
receiving the light by the light receiving element on the main substrate through
the opening point provided in the reel and the opening provided in the deck chassis.
