Provided are a substrate processing apparatus, a heating device, and a semiconductor device manufacturing method. The substrate processing apparatus comprises a process chamber configured to process a substrate. A heating element is installed at a peripheral side of the process chamber. An annular inner wall is installed at a peripheral side of the heating element. An annular outer wall is installed at a peripheral side of the inner wall with a space being formed therebetween. An annular cooling member is installed at the space for cooling. An actuating mechanism moves the cooling member between a contacting position where the cooling member makes contact with at least one of the inner wall and the outer wall and a non-contacting position where the cooling member does not make contact with any one of the inner wall and the outer wall. A control unit controls at least the actuating mechanism.