A plasma processing apparatus includes a process chamber, a substrate chuck disposed in the process chamber, and a temperature controller. The substrate chuck is configured to receive a substrate, and includes a cooling channel through which a coolant flows. The temperature controller is configured to control a temperature of the coolant supplied to the cooling channel. The temperature controller includes a cooler configured to cool the coolant supplied to the cooling channel, a heater configured to heat the coolant supplied to the cooling channel, and a 3-way valve configured to regulate a first flow rate of the coolant passing through the cooler and a second flow rate of the coolant passing through the heater.