A surface mounter includes: a component supply unit in which a plurality of components to be mounted are placed; a head unit which mounts a component on a circuit board by lifting the component from the component supply unit with suction; and a transfer unit including a carry-in portion with a single distribution lane, a mounting portion with dual working lanes, and a carry-out portion with a single carry-out lane, wherein a circuit board is transferred along the distribution lane and distributed to the mounting portion, components are mounted on the circuit board stopped at a position of the mounting portion, and the circuit board with the components mounted thereon is transferred out of the transfer unit along the carry-out lane. In the surface mounter, a number of circuit boards can be distributed to dual working lanes via a single distribution lane, not via common dual carry-in lanes, at higher working speed, so that working efficiency is improved. In addition, the surface mounter occupies less space.