PURPOSE: To investigate it on the shop side in which route a customer is moved, without applying an uncomfortable feeling to monitor the customer by confirming the position of a shopping basket by a signal.

CONSTITUTION: A receiving/transmitting means 1-1 is provided while being fitted to the shopping basket so as to transmit a specified signal for fixed time by receiving a certain signal, and a receiving/transmitting means 1-2 is provided while being fitted to a shelf and a register so as to receive the specified signal while transmitting a certain signal. Then, an information processing means 1-3 is provided to add the time and the place to the signals received at the shelf and the register. Thus, by time-sequentially processing the signals at a computer, the real shopping route can be grasped.