In a window regulator, and a method of producing the same, which moves a slider base along a guide rail via wires in accordance with rotation of a drum, includes a fitting portion having a first protrusion and a second protrusion provided on a drum housing which supports the drum, wherein the first protrusion protrudes from an abutting surface of the drum housing with which an end surface of the guide rail can come into contact and wherein the second protrusion protrudes from the abutting surface by a smaller amount of protrusion than that of the first protrusion, and the drum housing and the guide rail are joined by restricting movement of the guide rail in the thickness direction thereof by inserting the guide rail in between the first protrusion and the second protrusion. Workability during manufacturing of the window regulator is thereby improved.