In order to promote bone growth without damage of a growth plate to improve the stability of a procedure, the present invention provides an implant device for promoting bone growth, the device comprising: a first implant bar implanted to penetrate a metaphysis corresponding to the inside of a growth plate of a long bone to be treated； a second implant bar implanted to penetrate an epiphysis of the outside of the growth plate； and a stimulation elongation means disposed close to the external surface of the long bone to be treated and installed under skin tissues surrounding the long bone to be treated, and being elongated between end portions of the implant bars to increase a gap between the implant bars to cause the growth plate to be extended.
