A sales registration apparatus includes a commodity reader and a main body housing the reader. First attachment sections are distributed along a side surface of the main body at a fixed interval in the height direction. Each first attachment section is configured to permit the attachment of an additional component to the side surface. Each first attachment section is within a sub-portion of the side surface having a height that is a fixed unit height or an integer multiple of the fixed unit height. Cover sections are provided with each having a width equal to a width of the side surface and a height that is equal to the fixed unit height or an integer multiple of the fixed unit height. The cover section are attached to the side surface and cover any first attachment section not occupied by an additional component.