Disclosed is a buckle device that releasably locks an elastic band including a plurality of engaging portions in a lengthwise direction. The buckle device includes a buckle holder and a pair of slide buckles slidably fitted to the buckle holder. The buckle holder includes a pair of locking pins apart from each other and a pair of guide surfaces. A pair of elastic bands are hung on the locking pins respectively. The guide surfaces are inclined in opposite directions with respect to a plane passing through the pair of the locking pins. The slide buckle has a ratchet protrusion configured to engage the engaging portion of the elastic band and a slide surface configured to come into surface contact with the guide surface of the buckle holder. The slide buckle is movable between an unlocked position where the engaging portion pushes the ratchet protrusion in a first direction to allow a movement of the elastic band between the ratchet protrusion and the locking pin, and a locked position where the engaging portion pushes the ratchet protrusion in a second direction opposite to the first direction so that the ratchet protrusion presses the elastic band against the locking pin.
