SURFACE TREATMENT DEVICE

PROBLEM TO BE SOLVED: To provide a device for performing surface treatment to a surface of a workpiece having a groove or hole of a high aspect ratio.SOLUTION: The surface treatment device includes: a treatment chamber 3 for making a reactant gas chemically react with a surface of a workpiece 1; a reactant gas-supplying part 6 for supplying the reactant gas to the treatment chamber through an introduction passage of the reactant gas; and a pressure variation part 8 for varying the pressure of the treatment chamber by supplying an introduction gas to the treatment chamber separately from the introduction passage of the reactant gas. The surface treatment device is structured such that the introduction gas is supplied to the treatment chamber from the pressure variation part 8 through an introduction gas-supplying part 7 by periodically varying the pressure of the introduction gas to high pressure and low pressure in the range of 6,666-101,325 Pa, and thereby the pressure in the treatment chamber is varied to run the reactant gas into/from the hole or groove 2.