A bar steel cutting tool in which a fixed blade body and a rotary blade body that is capable of rotating around a first shaft, by operating a handle, are provided at the front end of a tool base for shearing bar steel with concave blades formed on outer peripheries of the fixed blade body and the rotary blade body. The handle is so constructed that the front end of a proximal portion of the handle thereof is supported by a second shaft at a position above the tool base and equipped with an elongated hole extending obliquely backwards from the second shaft. The rotary blade body has an arm portion extending backwards, and forms branch portions which nip both the right and left sides of the proximal portion of the handle at the rear end thereof.