A grain-oriented electrical steel sheet having a base steel sheet, an intermediate layer disposed to be in contact with the base steel sheet, the intermediate layer comprising an average Si content of 20 atomic% or more and an average O content of 30 atomic% or more as an overall average, and an insulation coating disposed to be in contact with the intermediate layer, wherein: the base steel sheet contains as determined in accordance with the description: Si: 0.8 to 7.0%, C: 0.005% or less, N: 0.005% or less, a total amount of S and Se: 0.005% or less, acid-soluble Al: 0.005% or less, Mn: 0% or more and 1.00% or less, Bi: 0% or more and 0.010% or less, B: 0% or more and 0.008% or less, Ti: 0% or more and 0.015% or less, Nb: 0% or more and 0.20% or less, V: 0% or more and 0.15% or less, Sn: 0% or more and 0.30% or less, Sb: 0% or more and 0.30% or less, Cr: 0% or more and 0.30% or less, Cu: 0% or more and 0.40% or less, P: 0% or more and 0.50% or less, Ni: 0% or more and 1.00% or less, and Mo: 0% or more and 0.10% or less, and a remainder being composed of Fe and impurities, the base steel sheet has a texture developed in a <001> orientation a surface of the base steel sheet has a groove which extends in a direction intersecting a rolling direction of the base steel sheet, wherein in a cross-sectional view of a plane parallel to the rolling direction and a sheet thickness direction of the base steel sheet, when a region between end portions of the groove is defined as a groove part, an average thickness of the intermediate layer of the groove part is 0.5 times or more and 3.0 times or less an average thickness of the intermediate layer other than the groove part, and an area ratio of voids in the insulation coating of the groove part is 15% or less. an intermediate layer disposed to be in contact with the base steel sheet, the intermediate layer comprising an average Si content of 20 atomic% or more and an average O content of 30 atomic% or more as an overall average, and an insulation coating disposed to be in contact with the intermediate layer, wherein: the base steel sheet contains as determined in accordance with the description: Si: 0.8 to 7.0%, C: 0.005% or less, N: 0.005% or less, a total amount of S and Se: 0.005% or less, acid-soluble Al: 0.005% or less, Mn: 0% or more and 1.00% or less, Bi: 0% or more and 0.010% or less, B: 0% or more and 0.008% or less, Ti: 0% or more and 0.015% or less, Nb: 0% or more and 0.20% or less, V: 0% or more and 0.15% or less, Sn: 0% or more and 0.30% or less, Sb: 0% or more and 0.30% or less, Cr: 0% or more and 0.30% or less, Cu: 0% or more and 0.40% or less, P: 0% or more and 0.50% or less, Ni: 0% or more and 1.00% or less, and Mo: 0% or more and 0.10% or less, and a remainder being composed of Fe and impurities, the base steel sheet has a texture developed in a <001> orientation a surface of the base steel sheet has a groove which extends in a direction intersecting a rolling direction of the base steel sheet, wherein in a cross-sectional view of a plane parallel to the rolling direction and a sheet thickness direction of the base steel sheet, when a region between end portions of the groove is defined as a groove part, an average thickness of the intermediate layer of the groove part is 0.5 times or more and 3.0 times or less an average thickness of the intermediate layer other than the groove part, and an area ratio of voids in the insulation coating of the groove part is 15% or less. Si: 0.8 to 7.0%, C: 0.005% or less, N: 0.005% or less, a total amount of S and Se: 0.005% or less, acid-soluble Al: 0.005% or less, Mn: 0% or more and 1.00% or less, Bi: 0% or more and 0.010% or less, B: 0% or more and 0.008% or less, Ti: 0% or more and 0.015% or less, Nb: 0% or more and 0.20% or less, V: 0% or more and 0.15% or less, Sn: 0% or more and 0.30% or less, Sb: 0% or more and 0.30% or less, Cr: 0% or more and 0.30% or less, Cu: 0% or more and 0.40% or less, P: 0% or more and 0.50% or less, Ni: 0% or more and 1.00% or less, and Mo: 0% or more and 0.10% or less, and a remainder being composed of Fe and impurities, the base steel sheet has a texture developed in a <001> orientation a surface of the base steel sheet has a groove which extends in a direction intersecting a rolling direction of the base steel sheet, wherein in a cross-sectional view of a plane parallel to the rolling direction and a sheet thickness direction of the base steel sheet, when a region between end portions of the groove is defined as a groove part, an average thickness of the intermediate layer of the groove part is 0.5 times or more and 3.0 times or less an average thickness of the intermediate layer other than the groove part, and