To provide a valve identification information registration system that allows valve identification information to be registered in a control device while reducing the number of transmission means.

A valve ID registration system is configured to register valve IDs, used in a tire air pressure monitoring system for a vehicle, in a control device. The valve ID registration system includes: a plurality of LF transmitters that respectively activate each group of tire valves, arranged on the same side of a vehicle, for each group by an activation signal Swk; a received-signal intensity acquiring part that detects each received-signal intensity B of radio waves, transmitted from the tire valves activated by the LF transmitters, when a door is opened or closed; and a valve ID registration part that registers the tire position by determining a change in received-signal intensity, caused by the door opening/closing, in the received-signal intensities obtained by the received-signal intensity acquiring part from the tire valves in each same group of tire valves selected by each LF transmitter.