A component mounting apparatus includes: a conveyor device for sucking and holding a substrate in a substantially vertical posture and conveying the substrate in a direction extending along its flat plate surface; a plurality of working devices for performing a working process for mounting areas in edge portions of the substantially vertical-postured substrate received from the conveyor device. In the component mounting apparatus, each of the working devices includes: a substrate holder for sucking and holding the substrate in a substantially vertical posture; a holder up/down device for moving the sucked and held substrate to a downward working position; a receiving member for supporting an edge portion of the substrate positioned in the working position from its back face side; and a working unit for performing the working process on the mounting areas of the edge portions of the substrate positioned in the working position from its front face side.