To provide an anti-theft implement which, once it is locked, a working tool cannot easily break an attachment part of an anti-theft target apparatus, the anti-theft implement itself or a locking tool, and also can prevent a case cover of the anti-theft target apparatus from being opened, without requiring a special contrivance on the anti-theft target apparatus.

A fixing base bottom of an anti-theft implement 10 with three pieces structure is fixed with a screw 50 itself used on the outside of a case 100 of an anti-theft target apparatus. A locked combination, which mounts a rotary cylinder with a canopy covering a screw head on a rotary cylinder with a base plate mounted on the outside of the case 100 with the fixing base bottom, is configured to freely rotate against the screw so as to realize an anti-theft implement difficult to be broken by a working tool.