According to one embodiment, an article sales data processing apparatus includes a list display control unit, a selection unit, an editing acceptance unit, and an update unit. The list display control unit causes a list of articles sold in one transaction to be displayed in the details area. The selection unit accepts selection of an article, of the articles displayed in the details area. The editing acceptance unit causes the display unit to display an editing screen for the sales data of the article selected by the selection unit, and accepts editing of the sales data. When the sales data displayed in the editing screen is edited, the update unit updates the sales data of the article selected by the selection unit, of the sales data of each article stored in the transaction storage unit, to the edited data.