To resolve problems of damage due to embrittlement of a heat insulating structural body, and nitriding in a nitrogen high pressure gas atmosphere while composing a support base by molybdenum based alloy material in a heating device for a hot isotropic pressure device.

The hot isotropic pressure device has a heater element 20 formed by a metal resistance wire, and the support base 21 holding the heater element 20 in a vertically divided state between a plurality of zones in a treatment chamber 6. The support base 21 is cylindrically formed using a woven fabric with density of 1.9-2.5g/cm3 formed by a ceramics long fiber material mainly composed of alumina.