To provide a
chemical solution spraying method for applying a
chemical solution to a surface of a canvas that is in contact with wet paper for a time period Tc of 0.03 seconds or more as uniformly as possible and enabling a sufficient amount of the
chemical solution to remain thereon while reciprocating a
nozzle device in a width direction with respect to the canvas. The present invention provides a chemical solution spraying method for spraying a chemical solution onto a canvas K1 having a loop shape in a side view while reciprocating two
nozzle devices S at the same speed along a rail L extending in a width direction of the canvas K1 with respect to the canvas K1, in which a time period Tc during which the canvas K1 is in contact with the wet paper X is 0.03 seconds or more, a time period Tn required for the
nozzle devices S to each one-way move is 0.5 to 10 minutes, a traveling speed Vp of the canvas K1 is 500 m / min or more, a length K of the canvas K1 is 20 to 80 m, a number of times of contact N of any point on a surface of the canvas K1 with the wet paper X during the time period Tn, the time period Tn, the traveling speed Vp, and the length K satisfy a relationship of N = (Tn·Vp) / K, and the number of times of contact N is 20 to 80, and a spray amount of the chemical solution is 0.1 to 500 mg / m2 as an effective component amount.