A component mounting method of mounting a component onto a board by a component mounting apparatus which includes a transportation device having a plurality of rails capable of transporting a plurality of boards in parallel is provided. The method includes positioning the rails so that a center of a mounting area in a forward-backward direction is at an intermediate position between corresponding parts of two component supply units, the mounting area covering an area in which two mounting heads mount components on one or more of the boards which are transported by the transportation device, and the intermediate position being equally distant in the forward-backward direction from the two component supply units; and alternately mounting the components in the mounting area between the two mounting heads.