To provide a plasma treatment device capable of efficiently treating a work without increasing the size of the entire device.

In the plasma treatment device in which a plasma generating coil is provided around a plasma generating outer chamber connected to a gas introduction unit for generating plasma, and a treatment chamber is disposed below the plasma generating outer chamber, an inner chamber having the sectional area smaller than that of the plasma generating outer chamber is provided inside the plasma generating outer chamber in a coaxial manner with the plasma generating outer chamber.