To improve work environment by preventing the occurrence of noise, dust and the like, sufficiently secure workability, furthermore, enable reduction in weight and miniaturization, and thereby enable a device to be carried in a work site.

This steel material cutting device is provided with a rotation driving mechanism, an eccentric shaft to be rotated by the aforesaid mechanism, a movable edge holding member Hm to be rocked by the eccentric shaft, a link member L1 regulating the movement of the movable edge holding member Hm, a movable edge Cm held to the movable edge holding member Hm, and with a fixed edge Cs cutting the steel material in cooperating with the movable edge Cm.