Grain-oriented electrical steel sheet and method of producing the same

A method of producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition comprising C:

• 0.001˜0.10 mass %, Si:
• 1.0˜5.0 mass %, Mn:
• 0.01˜4.0 mass %, one or two of S and Se:
• 0.01˜0.05 mass % in total, sol. Al:
• 0.003˜0.050 mass %, N:
• 0.001˜0.020 mass % and the remainder being Fe and inevitable impurities, subjecting to a hot band annealing if necessary, subjecting to single cold rolling or two or more cold rollings with an intermediate annealing therebetween to a final thickness, subjecting to primary recrystallization annealing, applying an annealing separator and finally subjecting to final annealing, wherein the primary recrystallization annealing is conducted so as to control a heating rate S1 between 500 and 600° C. to not less than 100° C./s and a heating rate S2 between 600 and 700° C. to not less than 30° C./s but not more than 0.6×S1, and as a main ingredient of the annealing separator is used MgO having an expected value μ(A) of citric acid activity distribution of 3.5˜3.8, an activity A of not less than 4.0 and a cumulative frequency F of 25˜45%.