The invention discloses a device for producing methyl formate by gas phase methanol carbonylation, which is characterized in that the device comprises a nitrogen gas pipeline, a carbon monoxide gas pipeline, a hydrogen gas pipeline, a nitric oxide gas pipeline, an oxygen gas pipeline, a methanol storage tank (1), a fluid pump (2), an esterification column (3), a first rectifying column (4), a waste water storage tank (5), a first condenser (6), a gas mixing box (7), a reactor (8), a heating furnace (9), a catalyst (10), a needle valve (11), an on-line gas chromatography system (12), a gas-liquid separator (13), a second rectifying column (14), a second condenser (15), a methyl formate storage tank (16), an air release valve (17), and a circulating pump (18). The device adopts a fixed bed reactor, is easy to separate the catalyst from the product, and is simple in operation; the reactor is a normal pressure reactor; and the money investment is less.