A band has an engaging projection part at one end, and an engaging grooves at the other end to adjust the connection in an annular shape. The band is movable forward but not movable backward relative to the other under the condition that the engaging projection part is locked to the engaging recessed part. A pair of hook parts capable of pulling both end parts by fingers of one hand is installed on both end parts. A buckle connected to the band includes a buckle main body having a bottom plate, a roof frame, and side plates for connecting the bottom plate to the roof frame. An operating plate is installed horizontally inside the roof frame, and has an engaging claw engageable with the band engaging grooves and a pressing part. The buckle and the band is made simple, and easily attached together.