A method of manufacturing a grain-oriented electrical steel sheet, comprising: performing hot rolling on a steel containing Si: 2.5 mass% to 4.0 mass%, C: 0.02 mass% to 0.10 mass%, Mn: 0.05 mass% to 0.20 mass%, acid-soluble Al: 0.020 mass% to 0.040 mass%, N: 0.002 mass% to 0.012 mass%, S: 0.001 mass% to 0.010 mass%, and P: 0.01 mass% to 0.08 mass%, further containing at least one kind selected from a group consisting of Ti: 0.0020 mass% to 0.010 mass% and Cu: 0.010 mass% to 0.50 mass%, wherein the steel optionally contains at least one kind of element selected from a group consisting of Cr: 0.20 mass% or less, Sn: 0.20 mass% or less, Sb: 0.010 mass% to 0.20 mass%, Ni: 0.010 mass% to 0.20 mass%, Se: 0.005 mass% to 0.02 mass%, Bi: 0.005 mass% to 0.02 mass%, Pb: 0.005 mass% to 0.02 mass%, B: 0.005 mass% to 0.02 mass%, V: 0.005 mass% to 0.02 mass%, Mo: 0.005 mass% to 0.02 mass%, and/or As: 0.005 mass% to 0.02 mass%, and a balance composed of Fe and inevitable impurities, to obtain a hot-rolled sheet; performing annealing on the hot-rolled steel sheet to obtain an annealed steel sheet; performing cold rolling on the annealed steel sheet to obtain a cold-rolled steel sheet; performing decarburization and nitridation annealing on the cold-rolled steel sheet to obtain a decarburized nitrided steel sheet; and performing finish annealing on the decarburized nitrided steel sheet, wherein the step for obtaining the decarburized nitrided steel sheet comprises: starting heating on the cold-rolled steel sheet in a decarburizing and nitriding atmosphere; then performing first decarburization and nitridation annealing at a first temperature for 15 seconds or more; and then, performing second decarburization and nitridation annealing at a second temperature for 15 seconds or more, the first temperature falls within a range of 700°C to 850°C, and the second temperature falls within a range of 850°C to 950°C. performing hot rolling on a steel containing Si: 2.5 mass% to 4.0 mass%, C: 0.02 mass% to 0.10 mass%, Mn: 0.05 mass% to 0.20 mass%, acid-soluble Al: 0.020 mass% to 0.040 mass%, N: 0.002 mass% to 0.012 mass%, S: 0.001 mass% to 0.010 mass%, and P: 0.01 mass% to 0.08 mass%, further containing at least one kind selected from a group consisting of Ti: 0.0020 mass% to 0.010 mass% and Cu: 0.010 mass% to 0.50 mass%, wherein the steel optionally contains at least one kind of element selected from a group consisting of Cr: 0.20 mass% or less, Sn: 0.20 mass% or less, Sb: 0.010 mass% to 0.20 mass%, Ni: 0.010 mass% to 0.20 mass%, Se: 0.005 mass% to 0.02 mass%, Bi: 0.005 mass% to 0.02 mass%, Pb: 0.005 mass% to 0.02 mass%, B: 0.005 mass% to 0.02 mass%, V: 0.005 mass% to 0.02 mass%, Mo: 0.005 mass% to 0.02 mass%, and/or As: 0.005 mass% to 0.02 mass%, and a balance composed of Fe and inevitable impurities, to obtain a hot-rolled sheet; performing annealing on the hot-rolled steel sheet to obtain an annealed steel sheet; performing cold rolling on the annealed steel sheet to obtain a cold-rolled steel sheet; performing decarburization and nitridation annealing on the cold-rolled steel sheet to obtain a decarburized nitrided steel sheet; and performing finish annealing on the decarburized nitrided steel sheet, wherein the step for obtaining the decarburized nitrided steel sheet comprises: starting heating on the cold-rolled steel sheet in a decarburizing and nitriding atmosphere; then performing first decarburization and nitridation annealing at a first temperature for 15 seconds or more; and then, performing second decarburization and nitridation annealing at a second temperature for 15 seconds or more, the first temperature falls within a range of 700°C to 850°C, and the second temperature falls within a range of 850°C to 950°C. starting heating on the cold-rolled steel sheet in a decarburizing and nitriding atmosphere; then performing first decarburization and nitridation annealing at a first temperature for 15 seconds or more; and then, performing second decarburization and nitridation annealing at a second temperature for 15 seconds or more, the first temperature falls within a range of 700°C to 850°C, and the second temperature falls within a range of 850°C to 950°C.