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 .