Method of producing grain-oriented electrical steel sheet and annealing separator application line

A method of producing a grain-oriented electrical steel sheet, the method comprising:

• subjecting a steel slab having a predetermined chemical composition to hot rolling, to obtain a hot-rolled steel sheet;
• subjecting the hot-rolled steel sheet to cold rolling once or twice or more with intermediate annealing therebetween, to obtain a cold-rolled steel sheet;
• subjecting the cold-rolled steel sheet to primary recrystallization annealing;
• applying a liquid or slurry annealing separator by a main line being a roll coater application device to the cold-rolled steel sheet after the primary recrystallization annealing;
• and
• thereafter coiling the steel sheet and subjecting the steel sheet to final annealing,
• wherein, before, after, or simultaneously with the application of the annealing separator, an additive aqueous solution for changing a composition of the annealing separator is adhered by an auxiliary line being a spray device to the cold-rolled steel sheet subjected to the primary recrystallization annealing at a weight ratio of 15% or less to a total of the liquid or slurry annealing separator and the additive aqueous solution so as to vary the composition of the annealing separator in at least one selected from a longitudinal direction and a width direction of the cold-rolled steel sheet.