Method of manufacturing grain-oriented electrical steel sheet

A method of manufacturing a grain-oriented electrical steel sheet, comprising

• subjecting a steel slab for grain-oriented electrical steel sheet 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 performed therebetween, to obtain a cold-rolled steel sheet,
• subjecting the cold-rolled steel sheet to pickling,
• subjecting the cold-rolled steel sheet to decarburization annealing,
• applying an annealing separator containing MgO to a surface of the cold-rolled steel sheet after the decarburization annealing, and
• subjecting the cold-rolled steel sheet applied with the annealing separator to final annealing, wherein
• in the pickling, a solution with an acid concentration of 1.0 mass % or more and 20 mass % or less and an Fe ion concentration of 2 mass % or more and 15 mass % or less is used, and
• in the decarburization annealing, a concentration of CO inevitably mixed in an atmosphere gas is maintained at 6 vol % or less.