To enable the stable surface treatment of a substrate by conveying the substrate having a surface on which projecting and recessing parts are formed in a striped pattern along a conveying path and jetting fluid to the surface of the substrate in the jetting direction that is determined according to the direction of the stripes in the striped pattern indicated on the surface of the substrate during that time.

When the surface of a substrate 2 is wet.treated, gas is blown from air knives 3, 4 to dry the surface of the substrate 2 in a drying process. In this substrate treating device, angles formed between vectors 5, 6 which the directions of gas streams jetted from the air knives 3, 4 are vertically projected on an imaginary surface including the surface of the substrate 2 to form and a vector 7 indicating the conveying direction of the substrate 2 are made 135°∼180° and 90°∼135° respectively. The air knives 3, 4 forming suitable gas streams according to the direction of stripes in the striped pattern indicated on the surface of the substrate 2 are selected and gas is jetted from the selected air knives 3, 4, causing a chemical to be effectively removed and the surface of the substrate 2 to be dried.