To provide a uniform heating method for heating a circular plate-form workpiece with uniform distribution of temperature and superior heating efficiency.

In the method in which a circular plate-form workpiece 1 is heated uniformly at temperatures with a lamp 3, one or more annular lamps are provided with its annular shape in parallel with the flat face of the plate- form workpiece, and a tube-shaped reflective body 4 is provided concentrically around the circumference of the lamp or the lamp group. On both sides of the plate-form workpiece, one or more circular lamps in parallel with their annular faces are provided, and a tube-shaped body is provided concentrically around the outer circumference of the lamp group facing both the sides of the workpiece.