To provide a bicycle key that is hardly stolen under a cooperation with an already-installed key because both a rear wheel and a bicycle parking stand are automatically fixed through an action for setting the bicycle parking stand when the bicycle is parked.

A key claw is turned around a key claw fixing pin through a key claw guide pin 8 arranged at the extremity end of a rod hardware 4 installed to perform a reciprocating linear motion within a key case 5 through a stand lever 1 having a structure synchronously following to a bicycle parking stand 13 so as to cause it to be pushed out toward a wheel spoke 15 and to prevent the wheel spoke 15 from being rotated. Moreover, a motion of a rod hardware stopper 9 is changed into a rotating motion through the reciprocating linear motion of the rod hardware 4 and simultaneously the rotating motion is transferred to a cylinder-type key body through a pin installed at the extremity end of the cylinder-type key body. A barrel segment of the cylinder-type key body is configured such that it does not perform any rotational action unless the key is inserted into it, and thereby all the operations for the bicycle parking work can be controlled only through performing an action for insertion and pulling-out of the key.