PURPOSE: To eliminate changing operation of various kinds of restricted bolt certainly, and simplify a sealing structure and operation.

CONSTITUTION: The restricted operating part 2 of a restricted bolt 1 is shunted in a bolt fitting hole 7, arid an adhesive layer 6 is provided between the restricted bolt 1 and the bolt fitting hole 7. The opening part 8 of the bolt fitting hole 7 is sealed by a sealing cover 10 through an elastic pressure spring 11. It is thus possible to prevent certainly changing operation of the restricted bolt 1 after shipment of an engine, since the restricted bolt 1 maintained on a regulating position by action of the elastic pressure spring 11 is fixed to the bolt fitting hole 7 by adhesive, and the restricted operating part 2 is sealed by the sealing cover 10 so as to disable contact from an outside. And also it is possible to simplify sealing structure and operation since the restricted bolt 1 is guided to penetrate the fitting hole 7 and the restricted bolt 1 is only sealed by the sealing cover 10.