To provide an insert fitting of simple constitution allowing a holder to be easily reused.

The insert fitting is screwed to a bolt fastening insert 1 embedded in a concrete structure 8, and inserted through a form 3 to fit the insert 1 to the form 3 before placing concrete. The insert fitting comprises a mounting bolt 2 screwed to the insert 1; a cylindrical holding body 5 composed of material incompatible with concrete and covering the periphery of the mounting bolt 2; and a nut for fixing the mounting bolt 2 to the form 3. The form 3 side end of the mounting bolt 2 is provided with an external thread part 2b screwed to the nut 4, and an engaging part 2a engaged with a removing tool.