A transaction assisting apparatus capable of automatically transacting chain orders. Chain order input unit accepts entry of a chain order and supplies the input chain order to chain order storing unit to be stored therein. Order detecting unit is supplied with an input buy order, and if the buy order placed is for the chain order, it notifies chain order processing unit that the buy order has been placed for the chain order. The chain order processing unit performs a selling/purchasing process with respect to the chain order for which the buy order has been placed. When the selling/purchasing process is completed, deleting unit deletes the corresponding chain order from the chain order storing unit. In the event the price of chained goods has changed, price changing unit changes the price of chain goods correspondingly in an interlocked manner. Display unit selectively displays, on display units, only those chain orders which satisfy certain conditions such as the presence of chained goods.