Abstract: A semi-self POS system according to the present disclosure includes: a registration apparatus and an accounting apparatus, the accounting apparatus being able to communicate with the registration apparatus, in which the accounting apparatus captures, when an addition of a product is requested, a bar code image of an additional purchase product and transmits an additional purchase notification including the bar code image to the registration apparatus, and the registration apparatus displays, when it receives the additional purchase notification, the bar code image included in the additional purchase notification, reads the displayed bar code image and thereby registers the additional purchase product, calculates a new total amount of payment obtained by adding payment of the registered additional purchase product to the total amount of payment, and transmits new accounting information including the new total amount of payment to the accounting apparatus.