To require the installation of only one motor, simplify a mechanism and allow manufacture at low cost by installing a drive device on a pipe roller at the rolling-down side, and providing a power part using a constant-torque spring on a pipe roller at the rolling-up side.

A blind 2 is wound into a rolling-up side roller pipe 1 laid on one end of the open part 6 of a window. A wire 4 is connected to both sides of an end bottom bar 3 at the end of the blind 2, so as to be taken up with a wire takeup pulleys 51 at both ends of a roller pipe 5. Furthermore, the roller pipe 5 is actuated with a motor-driven or a manually operated drive device for taking up the wire 4, thereby rolling down the blind 2. In addition, a constant-torque spring 91 is fitted to the roller end 11 of the rolling-up roller pipe 1 for the rotation thereof in a direction for rolling up the blind 2. As a result, the rolling-up side and rolling-down side of the blind 2 are pulled in opposite directions, thereby preventing the blind 2 from being slackened.