Cooling device used in metal tube bar continuous hardening and tempering heat treatment production line

The invention relates to a cooling device used in a metal tube bar continuous hardening and tempering heat treatment production line. The cooling device used in the metal tube bar continuous hardening and tempering heat treatment production line comprises a box body, wherein a feeding hole and a discharging hole are correspondingly formed in the left side wall and right side wall of the box body, four water inlets and one water outlet are formed in the outer side wall of the box body, and a water spraying device is arranged inside the box body. The cooling device used in the metal tube bar continuous hardening and tempering heat treatment production line is characterized in that the water spraying device comprises a first water spraying ring, a second water spraying ring, a third water spraying ring and a fourth water spraying ring which are sequentially arranged from left to right, the four water spraying rings are vertically arranged on one central axis and respectively correspond to the feeding hole and th