To incorporate a driving mechanism in a curtain rail by down-sizing the driving mechanism of a motor-driven curtain.

A curtain rail 110 has a hollow part extending along a longitudinal direction, and a lower surface constituting the hollow part includes an opening part opened along the longitudinal direction. On the inside of a right side surface constituting the hollow part, a toothed driven pulley 140 is rotatably mounted in the vicinity of an end (the other end) 112 of the curtain rail 110. An electric motor 120 is disposed in the hollow part in the vicinity of an end (one end) 113 of the curtain tail 110. The toothed drive pulley 130 is disposed between the electric motor 120 and the right side surface of the hollow part to which the toothed driven pulley 140 is mounted, and driven by the electric motor 120. A toothed belt 150 is stretched between the toothed drive pulley 130 and the toothed driven pulley 140. A curtain runner 160 is disposed in the hollow part of the curtain rail 110 and towed by the toothed belt 150.