To provide a holding structure for an object to be fixed, which can be easily assembled at a low cost in a simple configuration.

A holding structure for the object to be fixed is provided for holding an object to be fixed 30 via a nut member which is mounted on the guide groove 11 of a fixed frame member 10 to be moved and adjusted to any arbitrary position. The nut member includes a nut part formed by penetrating an internal thread, and an elastic body fixed to the nut part. The guide groove 11 includes a groove part 11a for moving the nut member to the arbitrary position to engage and hold the nut member, and an opening part 11b for mounting the nut member on the groove part 11a. In a state where the elastic body is compressed, the nut member is inserted into the groove part 11a while fitting the nut part and the elastic body to the opening part 11b, one end part of the nut part protruding from the opening part 11b is pushed into the groove part 11a from the opening part 11b, the elastic body is compressed and rotated, both end parts of the nut part are energized to the inside of the opening part 11b by the elastic body, and the nut member mounted on the guide groove 11 is held not to be displaced.