To provide a heat treatment device having good response to temperature control, and capable of shortening a start-up time and a termination time of a heat treatment device and reducing a weight of the device.

This heat treatment device A for a glass substrate is provided with heater devices 32 capable of generating heat by power distribution, and arranged in multiple stages at prescribed intervals inside of a furnace body. The heater is formed by holding a heating element by thin film-shaped sheet bodies having a thickness of 0.01-1 mm, like a sandwich.