The invention relates to a high-precision pen-type
injector which comprises an injection button, a
dose adjusting knob, an engaging and disengaging
ratchet, an engaging and disengaging spring, a spiral sleeve, a screw, a spiral
ratchet, a fixed
ratchet wheel
assembly, a main body upper housing, a reset rotary knob, a reset spring, a
cartridge case bin and a
dose display sleeve. The screw is in threaded connection with a threaded hole of the spiral ratchet, a matched plane is arranged on the screw, the reset rotary knob is provided with a flat reset rotary knob hole matched with the screw, thereset rotary knob is installed on the screw through the reset rotary knob hole, a second one-way ratchet is arranged on the end face of the reset rotary knob, a first one-way ratchet matched with thesecond one-way ratchet is arranged on the fixed ratchet wheel
assembly, one end of the reset spring abuts against the reset rotary knob, the other end of the reset spring abuts against the fixed ratchet wheel
assembly, and the
cartridge case bin is fixedly connected with the end of the main body upper housing. The high-precision pen-type
injector saves effort in injection and is high in injectionprecision.