According to one embodiment, a portable terminal apparatus, which is a sales supporting apparatus, is used by a person in charge of commodity sales when the person in charge of commodity sales have a business negotiation with a customer concerning a luminaire or a lighting system including a semiconductor light-emitting light source. The portable terminal apparatus includes a touch pane, which is a display section, and a control section configured to control the touch panel. The control section enables input of a desired specification concerning at least one of a geometric extent of a beam of rays, a color temperature, and a color rendering index and causes the touch panel to display a commodity list of commodities that meet the input desired specification.