PURPOSE: To improve consistency between a heater set temperature and a substrate temperature as well as temperature following properties by forming a plurality of gas exhaust openings arranged in multiple circumferences or spirals on a bottom side of a recessed part adjacent to a substrate rear of an upper part of a heating block whereon a substrate is mounted and by providing a partition wall inside the recessed part along the circumferences.

CONSTITUTION: A copper block 2 is heated by a ceramic heater 4; temperature set thereof depends on temperature measurement of a thermo couple 3. Argon gas is introduced from a gas introduction port 5 and heated when passing through the block 2 to heat a substrate 1 mounted on an upper side of the block 2. The upper part of the block 2 forms a recessed part 7 allowing a periphery thereof to remain and a gas exhaust port 10 is arranged in multiple circumferences in a bottom side. A partition wall 11 is provided along each circumference, and the argon gas introduced from the gas introducing port to the block 2 passes through gas introducing paths 6, 6' and is jetted from the gas exhaust port 10 to the recessed part 7 uniformly and applied to a rear of the substrate 1 which is tightly bonded to the block 2 at a peripheral part 9 thereof to heat the substrate 1.