A method of producing a busbar structure includes a busbar arranging step for arranging a plurality of the busbars at predetermined positions in a cavity which is formed between a fixed mold and a movable mold which can be clamped and opened with respect to the fixed mold, and clamping the two molds, a resin filling step for filling molten resin into the cavity in which the busbars have been arranged, and a busbar fixing step for hardening the molten resin which has been filled thereby to fix the busbars at predetermined positions with the hardened resin, and opening the two molds. Interposed pins to be interposed between the busbars which are arranged in close proximity to each other are detachably disposed in an engaged part of the movable mold, and removed from a molded product when the two molds are opened.