Abstract: A single sliding sash in which a sliding door, which is positioned on the internal side of a fixed section when open and which closes an open section when closed, is fixed to a window frame. This window frame has the fixed section on one side thereof and the open section on the other side. Upper guide rails are provided on a head. The sliding door is supported, with the aid of sliding door support pieces, by a pair of sash pulleys, which travel along the upper guide rails so as to change the position of the sliding door in the direction of the shash pulleys. A bend space is provided close to a door front edge hard frame of the upper guide rails. One end of the bend space communicates with a guide space which is provided between the guide rails, whereas the other end of the bend space is arranged on the external side of the guide space.