To provide a box body for an underground structure easily fixing an internal cylinder body at a desired height to an external cylinder body.

In the box body for the underground structure with the external cylinder body 2, in which a female screw section 2d is formed to an inner peripheral surface, and the internal cylinder body 3, which is installed into the external cylinder body 2 and in which a male screw section engaged with the female screw section 2d is formed to an outer peripheral surface, the box body is constituted so that the internal cylinder body 3 is composed of an upper cylinder body 4 and a lower cylinder body 5, and male screw sections 4d and 5d are formed to each outer peripheral surface of the upper cylinder body 4 and the lower cylinder body 5.