To provide a lock piece which can easily be detached from an article without using a pair of scissors nor a cutter.

Disclosed is the lock piece for the price tag etc., which comprises a lateral rod portion 1a, a head portion 4B, and a filament portion 1c connecting those members and is made of a synthetic resin on the whole, the lock piece for the price tag etc., being in a shape wherein the head portion is branched to the right and left from an end of the filament portion, and extended and connected together to form a right-left symmetrical loop, for example, in a shape drawing an outline of a polygonal shape of a spade, a circle, an ellipse, a triangle, or a quadrangle, or a shape having rounded corners of one of them, or a shape of a combination of them.