A jig for pressing a gas analysis monocell according to the present invention comprises: a first plate and a second plate which face each other with a monocell therebetween; a first auxiliary pad positioned between the first plate and the monocell; and a second auxiliary pad positioned between the second plate and the monocell, wherein the first plate and the second plate are formed of a thermosetting resin. When analyzing a gas generated from the monocell during a primary charge, the jig for pressing the monocell according to the present invention presses the thin monocell to prevent a gap from forming between electrodes due to the primary charge, and thus has an effect of deriving more reliable analysis results.