A registration settlement apparatus comprises a first determining module configured to determine contents of a transaction in response to an operation by a first operator; a second determining module configured to determine contents of the transaction in response to an operation by a second operator facing the first operator across the registration settlement apparatus; a determination control module configured to enable one of the first and second determining modules, and to switch to the determining module enabled for the determination on contents of a transaction started thereafter in response to a button operation by the second operator before the determination on contents of one transaction is started; and a settlement module configured to perform a settlement processing of calculating a settlement amount based on the contents of the transaction determined by the determining module enabled, and settling the calculated settlement amount in response to an operation by the first operator.