A clasp including: a first extension link that is formed in a U-shape and in which a closed end side is rotatably supported at one end of a clasp cover of a band; and a second extension link connected to an open end side of the first extension link via a connecting member, wherein, the second extension link is fixed to the first extension link at a position different from a connected position in the connecting member, and the first extension link is fixed to the clasp cover at a position different from the one end of the clasp cover where the first extension link is rotatably supported.