Linear groove formation method and method of producing grain-oriented electrical steel sheet

A linear groove formation method comprising:

• forming a resist coating on at least one surface of a metal strip;
• thereafter irradiating the resist coating with a laser while scanning the laser in a direction crossing a rolling direction of the metal strip, to remove the resist coating in a part irradiated with the laser;
• and
• thereafter performing etching treatment to form a linear groove in a part of the metal strip in which the resist coating is removed,
• wherein the resist coating contains 20 mass % or more of an inorganic compound in terms of solid content, and
• on the surface of the metal strip which has been coated and etched, the laser has an elliptic beam shape whose ratio of a major axis length to a minor axis length is 5.0 or more, and has a beam diameter of 10 μm or more and 100 μm or less in a direction orthogonal to a scanning direction of the laser.