<p>The problem addressed by the present invention is the provision of a plasma treatment device with which it is possible to easily control the electron energy distribution of plasma in accordance with the type of gas molecules to be dissociated and the dissociation energy thereof. A plasma treatment device (10) according to the present invention comprises: a plasma treatment chamber (11); a plasma production chamber (12) that communicates with the plasma treatment chamber (11); a high-frequency antenna (16) for producing plasma; a plasma control plate (17) for controlling the electron energy of the plasma; and an operation rod (171) and a movement mechanism (172) for adjusting the position of the plasma control plate (17). By means of this plasma treatment device (10), it is possible to control the electron energy distribution of the plasma produced inside the plasma production chamber (12) simply by using the movement mechanism (172) to move the operation rod (171) longitudinally in order to adjust the distance between the high-frequency antenna (16) and the plasma control plate (17). It is therefore possible to easily treat plasma in accordance with the type of gas molecules to be dissociated and the dissociation energy thereof.</p>
