Hexagon Head Steel Wrench is a T-type socket wrench having three hexagonal rods on three ends of a Y-shaped handle, and three double-head hexagon sockets of successive hexagonal holes mounted on the three hexagonal rods and stopped at respective first positions by respective first steel balls for turning hexagon head screws. Each double-head hexagon socket is moved inwards on the respective hexagonal rod and stopped at a respective second position by a respective second steel ball permitting a hexagon bit of different size on the respective hexagonal rod to project out of the respective double-head hexagon socket for turning a socket head screw.