To provide a management system for bicycles and a parked bicycle managing device that can speedily and easily find a stolen bicycle.

A registration certificate in which an IC chip having recorded registration data is incorporated is stuck on a bicycle and the registration data are read by a terminal, which when reading the registration data, acquires position information through GPS. Parking information is transferred from the terminal to a terminal device, which sends the parking information to a parked bicycle managing device through a network. The parked bicycle managing device once receiving the parking information stores position information while making it correspond to the registration data and performs recognition processing for a stolen bicycle and a bicycle left alone based upon the position information at this time.