Provided are a substrate temperature control method and a plasma processing apparatus using the method. The method includes: disposing a substrate on a placing table provided in a vacuum processing chamber; supplying a heat conduction gas between a rear surface of the substrate and the placing table; detecting a pressure of the heat conduction gas; comparing the detected pressure value with a set pressure value; controlling the supply of the heat conduction gas so that the detected pressure value becomes the set pressure value; and alternately repeating a first period where the set pressure value is set to be a first set pressure value that is higher than a low pressure value and equal to or higher than the lowest limit pressure value and a second period where the set pressure value is set to be a second set pressure value that is lower than the low pressure value.