The invention discloses a stamping device used for three-form invoices, and belongs to the technical field of office automation equipment. The technical problem that an existing invoice stamping machine cannot automatically stamp three-form invoices is solved. The stamping device used for three-form invoices comprises a rack, a first invoice stamp, a second invoice stamp, a first rail capable of vertically sliding along the rack, and a first driving mechanism driving the first rail to vertically reciprocate. The first driving mechanism comprises a first drive motor, a first controller controlling the first drive motor to operate intermittently, a first rotary disc coaxially connected to the output end of the first drive motor, and a first connecting rod with one end eccentrically hinged to the first rotary disc and the other end hinged to the first rail. Two horizontal rods are fixedly connected to the first rail, the first invoice stamp is fixed to one horizontal rod, and the second invoice stamp is fixed to the other horizontal rod.