To obtain a glass fiber for rubber reinforcement, capable of providing a rubber product excellent in heat resistance, water resistance and resistance to fatigue from flexing by embedding the glass fiber into rubber and provide a method for producing the glass fiber.

A first liquid containing a rubber latex and a resorcin- formaldehyde water-soluble condensate is attached to glass fiber bundle to form a first coated layer and a second liquid containing silicone is attached onto the first coated layer to form a second coated layer and further, a third liquid containing a halogen-containing polymer and isocyanate is attached onto the third coated layer to provide the objective glass fiber for rubber reinforcement.