To provide a surfboard or a paddleboard, which is easy to assemble, is surely fixable, is dividable into two, and is easy to carry.

A board manufactured using carbon fiber or glass fiber and an epoxy resin in order to reduce weight is divided into two, two holes are provided respectively on cut surfaces, female pipes 3 and 4 are buried there, two male pipes 13 and 14 to be fitted to both female pipes are used to match both of them, and both cut surfaces are surely fixed by a screw and a bridging plate. Also, both cut surfaces are provided with a bridging member by irregularities, and the cut surfaces are surely fixed.