An optical fiber coupler in which damage to a pumping light source can be suppressed even if signal light leaks and an optical fiber amplifier using the optical fiber coupler are provided. An optical fiber coupler includes: a first optical fiber having a core and a clad coating the core; a second optical fiber having a core; and a fusion-drawn portion formed by arranging the first optical fiber and the second optical fiber so that their longitudinal directions are in the same direction and fusing the clad of the first optical fiber and the core of the second optical fiber. The clad of the first optical fiber has a larger refractive index than the core of the second optical fiber.