Temperature monitoring device, temperature monitoring method, and composite material manufacturing method

A composite material manufacturing method, the composite material being used in a temperature monitoring method using a temperature monitoring device that is disposed in a furnace together with a composite material, in which the temperature monitoring device includes

• a pair of inner components that each have a temperature detection surface and overlap each other such that the temperature detection surfaces face each other,
• a temperature detecting unit that is disposed so as to be sandwiched between the temperature detection surfaces, and
• at least a pair of outer components that are provided on opposite sides to the temperature detection surfaces of the pair of inner components respectively,
• the composite material manufacturing method comprising:
• a thickness determination step of determining a dimension of a gap between the inner component and each of the outer components in a thickness direction based on a heat capacity of the composite material;
• an adjustment step of adjusting the dimension determined in the thickness determination step, and
• an air layer forming step of forming an air layer between at least one of the inner components and at least one of the outer components.