The present invention provides a heat treatment apparatus having a high degree of freedom of an outlet design and capable of adjusting the rate of a reduction in the temperature of each part of a heater without using an adjustment valve. The heat treatment apparatus having a simple flow path structure can be constructed with simplified sealing and a reduced cost.The heat treatment apparatus 1 includes a process chamber 2, a tubular heater 3, a heat exhaust system 25 and a cooling section 26. The process chamber 2 accommodates objects W to be placed in multiple stages and to be treated. A predetermined heat treatment is performed in the process chamber. The heater 3 surrounds an outer circumference of the process chamber 2 and heats the objects W to be treated. The heat exhaust system 25 is adapted to exhaust an atmosphere present in a space 24 existing between the heater 3 and the process chamber 2. The cooling section 26 is adapted to blow a cooling fluid into the space 24 to cool the atmosphere. The heater 3 includes a tubular heat insulator 17, a heat generating resistor 18 and an outer shell 20. The heat generating resistor 18 is provided on an inner circumference of the heat insulator 17. The outer shell 20 is provided on an outer circumference of the heat insulator 17. The cooling section 26 includes at least one annular flow path 28 and an outlet 29. The annular flow path 28 is arranged between the heat insulator 17 and the outer shell 20. The outlet 29 is provided in the heat insulator 17. The outlet 29 is arranged to ensure that the cooling fluid is blown out of the outlet 29 toward a vertical central axis of the heat insulator 17 or in a direction oblique to the direction toward vertical central axis of the heat insulator 17.