A method for producing the optical coupler includes mounting a first conversion element on an upper surface of a first terminal plate, mounting a second conversion element on an upper surface of a second terminal plate, supplying a translucent primary mold resin in a fluidized state to the upper surfaces of the first terminal plate and the second terminal plate such that the first conversion element and the second conversion element are covered with the primary mold resin, curing the primary mold resin while inverting vertically the first terminal plate and the second terminal plate to retain the primary mold resin in a state in which the primary mold resin hangs from the first terminal plate and the second terminal plate, and covering a surface of the primary mold resin with a secondary mold resin having a refractive index lower than that of the primary mold resin.