A crankshaft heat treatment device may include a base frame, a jig frame in which a crankshaft is rotatably supported and that is disposed to be able to move in a horizontal direction and in a vertical direction at the base frame, and a laser unit that is disposed in a predetermined fixed position and irradiates laser beam to a pin portion and a journal portion of the crankshaft so as to treat the pin portion and the journal portion with heat.