Abstract: A sales data processing device includes an operator display unit, a customer display unit and a display control unit. The operator display unit displays a screen for an operator to operate. The customer display unit displays a screen for a customer to view. The display control unit displays, on the screen of the operator display unit, a recommendation button to start displaying information on a recommended item on the screen of the customer display unit. When the recommendation button is operated by the operator, the display control unit displays the information on the recommended item on the screen of the customer display unit and displays an input button to input whether the customer purchases the recommended item on the screen of the operator display unit.

Abstract: A commodity registration device according to the present invention includes: a photographing unit that photographs an object as an image; a voice input unit that receives a voice; and a control unit that recognizes a commodity by using, as auxiliary information to recognize the object as a commodity, the voice received from the voice input unit during a predetermined period before and after timing including the timing of detecting that the object is photographed by the photographing unit as the image.