Abstract: A heater unit has excellent uniform heat properties in a wafer placement surface, and is capable of rapid temperature increase and rapid cooling, also has high rigidity. A heating and cooling device that includes the heater unit is used as a manufacturing or inspection apparatus and is used for work with glass substrates or semiconductor substrates for flat panel displays. The heater comprises a first uniform heat plate having a placement surface on which a substrate is placed, a second uniform heat plate for supporting the first uniform heat plate, and at least one layer of a insulated resistance heating element provided between the first uniform heat plate and the second uniform heat plate. The first uniform heat plate and the second uniform heat plate have a differing thermal conductivity and differing Young's modulus.