An opening/closing direction restriction mechanism for a manual shutter device and an opening/closing direction restriction mechanism for a suspended sliding door device. This opening/closing direction restriction mechanism is provided with: a flange fixedly mounted on a fixed shaft; a bracket which is loosely fitted to the fixed shaft and can be integrally rotated with a winding member; and a two-way clutch which can be switched between a reverse rotation inhibited state in which the revolution of a planetary external gear along a winding direction of the winding member is allowed and the revolution of the planetary external gear along an unwinding direction is inhibited, and a forward rotation inhibited state in which the revolution of the planetary external gear along the winding direction of the winding member is inhibited and the revolution of the planetary external gear along the unwinding direction is allowed.