To provide a glass roving capable of forming a fiber-reinforced resin of stable performance by suppressing the lowering of manufacturing efficiency or the like during manufacturing the fiber-reinforced resin, a traverse device for manufacturing the glass roving, and a method of manufacturing the glass roving.

This glass roving 10 is made by winding up a glass filaments constituting a glass strand 20 so as to have a ply-twist of alternative right and left twists in the length direction of the filament. The traverse device for manufacturing the glass roving 10 is formed with a thread groove at a tread guide member of the device, and the ratio of the width of the thread groove to the thickness of the tread guide member in a direction of the thread guide of the thread groove is not smaller than 1.0. In the manufacturing method of the glass roving, this glass roving 10 is manufactured by coating the glass filament with a sizing agent, winding up a glass filament bundle, traversing with a traverse width of from 250 mm to 400 mm, into a roll using a traverse device for a glass roving manufacturing which has the thread guide member, and then being dried.