Temperature uniformity in a mounting surface of a mounting table is improved. A plasma processing apparatus includes the mounting table having thereon the mounting surface on which a work-piece serving as a plasma processing target is mounted; a coolant path formed within the mounting table along the mounting surface of the mounting table; and an inlet path connected to the coolant path from a backside of the mounting surface of the mounting table and configured to introduce a coolant into the coolant path. The inlet path is extended from the backside of the mounting surface of the mounting table such that an extension direction of the inlet path is inclined at an angle greater than 90° with respect to a flow direction of the coolant flowing through the coolant path, and then, connected to the coolant path.