It is intended to provide a substrate treatment device capable of adjusting both of a growth speed and an etching speed in a selective epitaxial growth, avoiding particle generation from nozzles, and achieving good etching characteristics. A substrate treatment device for selectively growing an epitaxial film on a surface of a substrate by alternately supplying a raw material gas containing silicon and an etching gas to a treatment chamber, the substrate treatment device being provided with a substrate support member for supporting the substrate in the treatment chamber, a heating member provided outside the treatment chamber for heating the substrate and an atmosphere of the treatment chamber, a gas supply system provided inside the treatment chamber, and a discharge port opened on the treatment chamber, wherein the gas supply system comprises first gas supply nozzles for supplying the raw material gas and second gas supply nozzles for supplying the etching gas.