An electric curtain opening and closing device includes a curtail rail and a movable body arranged in the curtail rail. The curtain rail has a hollow portion that is hollow extending in a longitudinal direction, and an opening opened in the longitudinal direction on its bottom face. Power supply patterns for supplying electricity are arranged inside left and right side faces that constitute the hollow portion in the longitudinal direction. The movable body has electrodes in contact with the respective power supply patterns, an electric motor receiving electricity through these electrodes to positively or negatively rotate, and a hanging portion for hanging a curtain. The movable body is driven to move by the electric motor. When the movable body is arranged in the hollow portion of the curtain rail, the hanging portion protrudes from the opening of the curtain rail.