A light-source apparatus includes a light-source chip, a case, first and second electrically-conductive parts, a substrate, an electromagnetic shield plate, an electrically-conductive layer and an electrically-conductive unit. The light-source chip is received in the case. Each of the first and second electrically-conductive parts is a part of the case. The case is mounted to the substrate. The electromagnetic shield plate covers at least part of the substrate. The electrically-conductive layer is formed on the substrate and electrically connected with both the second electrically-conductive part and the electromagnetic shield plate. The electrically-conductive unit is provided to electrically connect the first electrically-conductive part and the electromagnetic shield plate.