A method for producing an optical device includes steps of: providing a first mold set, a second mold set, and an inner mold member cooperating with the first mold set to define a first molding cavity; filling a first plastic material into the first molding cavity so as to form a first molded object including a first molded element; placing the first molded object and the inner mold member into the second mold set to cooperatively define a second molding cavity; filling a second plastic material into the second molding cavity so as to form a second molded object including a second molded element; and disconnecting the first and second molded elements from the first and second molded objects.