Disclosed is an efficient heat treatment method which can be performed in a short time. Specifically disclosed is a method for heat-treating a steel material wherein a plastically deformed steel work is introduced into a heat treatment furnace when the work still retains the heat applied thereto during the plastic deformation, then the work is heated preferably at a heating rate of 15-50 DEG C./min and held at a temperature between Ac1 and Ac3 for 10 minutes or less, and then the work is slowly cooled at a cooling rate of 5-45 DEG C./min. This heat treatment method enables to easily produce a steel material having a uniform metal structure by simple facilities.