Abstract: A C.music-sharp. key roller for the foot tube of a flute is disclosed which is constructed such that a connector shaft hole within the connector is made in the form of a through hole by additionally providing an extended threaded through portion, and the opposite ends of the said through hole are fitted with an auxiliary bolt and with the leading end of the roller shaft, thus forming a double lock system. With this arrangement, the setting of the gap between the roller and connector during assembly is made easy, the loosening of the thread portions is prevented, and resetting is made possible upon the wearing-out of the sliding portion of the roller and the roller shaft.