To provide an anti-theft case capable of preventing a locking claw from being pushed in by a hand.

In the anti-theft case, an insertion member 13 to be guided by a guide means as an insertion passage formed in the case is inserted from an insertion port formed at a required position of a display case K consisting of a box body 1 and a lid body 4; a hooking means capable of preventing the opening of the case by the hooking relationship is provided on the insertion member, the box body and the lid body; a plurality of non-magnetically attracted locking claws 17 to be pushed back against the restoration force according to the insertion are provided on the slide line of the insertion member; and through holes 18 in which the respective locking claws are brought in an engagement relationship as the insertion of the insertion member is completed are formed in peripheral walls 8, 6 of the case. Receiving parts 21 projecting in the reverse direction of the insertion port are provided on a lower edge of an end located on the insertion port side of the through holes, and projecting parts 22 to be hooked to the receiving parts according to the slide of the insertion member in the escaping direction are provided on a free end of the locking claws.