A frit includes SiO.sub.2 as a main component, and has a Na concentration of 300 mass ppm or less as determined by ICP atomic emission spectroscopy.

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in which, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 m or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction .sub.0-pb in a unit of m/m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction .sub.0-pa in a unit of m/m when the grain-oriented electrical steel sheet is heat-treated at 800 C. for 4 hours and then excited up to 1.7 T satisfy 0.02.sub.0-pb.sub.0-pa0.20.