A substrate treatment apparatus according to an embodiment of the present invention includes a chamber, a stage, a gas discharger, a plasma generator, and a rotation mechanism. The stage supports a semiconductor substrate in the chamber. The gas discharger discharges a film formation gas toward the semiconductor substrate from a position opposing the stage. The plasma generator is provided on the gas discharger and generates plasma in the chamber during discharge of the film formation gas. The rotation mechanism rotates the stage during generation of the plasma.