A commodity sales data processing apparatus comprises a wireless communication section; an input section configured to input commodity specification information specifying a commodity; a determination unit configured to determine whether or not wireless communication with a portable terminal of a customer is established; and a communication unit configured to wirelessly transmit information for the display of settlement information based on the commodity specification information input from the input section on the portable terminal from the wireless communication section to the portable terminal on condition that the determination unit determines that wireless communication with the portable terminal is established.