The invention discloses a lens module assembly device which is used to assembly at least one accessory to cylinder. The lens module assembly device includes: at least one contraposition platform to preset said accessory; a contraposition assembling platform to position and fix said cylinder; at least one dispenser each of which separately includes at least one vacuum nozzle to assembly said accessory preset to the cylinder of platform to form lens module when said accessory is transferred to said contraposition platform. Said lens module assembly device can accomplish automatic assembly of multiple accessories and cylinders on a single platform, loss ratio induced by conveyance and switching can be saved, at the same time speed of assembly can be increased, productivity is increased, automatic large scale production of lens module can be realized.