Provided are a radical monitoring apparatus capable of monitoring electrical diagnosis of a radical produced by direct plasma or remote plasma and the amount of change of the produced radical, and a plasma apparatus including the radical monitoring apparatus. The plasma apparatus includes a process chamber in which a plasma process is performed, a dielectric film in the process chamber and surrounding sides of a plasma discharge space in the process chamber, and a sensor inside the dielectric film and configured to monitor plasma to thereby monitor a radical generated in the plasma.