PURPOSE: To seal an adjuster bolt which controls fuel to an engine or an adjuster bolt which controls power of a power station, current of electronic equipment, or the like.

CONSTITUTION: This device comprises an adjuster bolt 58 protruding from a mounting member 60 with which it meshes threadedly, an inner member having an engaging part with resiliency on the outer circumference thereof, an outer member having an engaging part engaging with an engaging part of the inner member while covering the inner member. The outer member is so arranged as not to be separated easily.