In a method for removing deposit that has attached to a main surface of a substrate from the main surface of the substrate using air knife units where a slit portion is formed so that a fluid can be discharged in band form, a fluid introduction path having an approximately uniform form in the direction perpendicular to the direction in which a number of air knife units move relative to the substrate is formed between the air knife units and the main surface of the substrate while the air knife units move relative to the substrate, a fluid is discharged toward the fluid introduction path from a slit that is formed in the rear portion of the above described air knife units, and then, passes through the fluid introduction path so as to be led to a wall surface that is formed so as to face the front portion of the air knife units or the fluid which has the appearance of a wall surface, and furthermore, deposit on the substrate that has attached to the substrate is led away from the main surface of the substrate, together with said fluid, via a fluid lead-out path of which the cross sectional area of the low path is greater than that of the fluid introduction path, and which is formed between the air knife units and the wall surface.