Fixture capable of focusing by rapid and convenient use of relay mirror

Disclosed is a fixture capable of focusing by rapid and convenient use of a relay mirror. The fixture comprises the relay mirror and is characterized by further comprising a connection cylinder fixedly connected with the tail portion of the relay mirror, a fixation cylinder in threaded connection with the tail portion of the connection cylinder, a rotary cylinder which is movably fixed between the connection cylinder and the fixation cylinder and is capable of 360-DEG rotation, and a focusing elevating cylinder connected with the rotary cylinder. A focusing pawl for adjusting the focal length of a lens module is fixed at the bottom of the focusing elevating cylinder. The fixture has the following advantages: 1, the focusing pawl is arranged at the bottom of the focusing elevating cylinder, such that at the time when the relay mirror performs focusing detection, the focal length of the lens module can be adjusted, thus focusing is more convenient and rapid, and the work efficiency is improved; 2, the fixture c