To provide a reverse winding preventing device capable of preventing reverse winding of elevating belt during winding down thereof and safely controlling elevation of a belt type elevator.

This belt type elevator using elevating belt wound around a winding drum is provided with a reflection tape 6 on a winding shaft of the winding drum 2 and a photoelectric switch 7 irradiating a surface of the reflection tape 6 and receiving reflection light. When elevating belt 4 is unwound from the winding drum 2 and the reflection tape 6 on the winding shaft is exposed, the photoelectric switch 7 sends a stop signal to a drive control device of the winding drum 2.