A surface treatment method using a plasma treatment apparatus which has an electric discharge generation portion facing a surface of a substrate with a gap therebetween, the substrate being placed on a supporting body, and a construction in which the gap is supplied with a treatment gas, the method includes: applying different voltages between the electric discharge generation portion and the supporting body such that plasma is obtained from the treatment gas supplied to the gap; moving one of the electric discharge generation portion and the substrate relative to the other in a first direction, while the surface of the substrate being exposed to the plasma; and moving, after the relative movement in the first direction and the exposure above referenced, one of the electric discharge generation portion and the substrate relative to the other in a second direction opposite to the first direction, while the surface of the substrate being exposed to the plasma.