[Object] An optical fiber coupler in which damage to an pumping light source can be suppressed even if signal light leaks and an optical fiber amplifier using the optical fiber coupler are provided.[Solving Means] An optical fiber coupler 100 includes: a first optical fiber 10 having a core 11 and a clad 13 coating the core 11; a second optical fiber 20 having a core 21; and a fusion-drawn portion 110 formed by arranging the first optical fiber 10 and the second optical fiber 20 so that their longitudinal directions are in the same direction and fusing the clad 13 of the first optical fiber 10 and the core 21 of the second optical fiber 20. The clad 13 of the first optical fiber 10 has a larger refractive index than the core 21 of the second optical fiber 20.