Abstract: A concise and low cost mobile object management system which is capable of monitoring a state of a mobile object via a wireless transmitter-receiver having a wireless LAN function is provided. The mobile object management system includes a sensor for acquiring various information of a mobile object, a clock information acquisition unit, a memory unit for storing data, and a wireless LAN transmitter-receiver unit, each controlled by a Central Processing Unit, and transmits wirelessly a state of a measured object on the mobile object, location information, and clock information. By adopting a wireless LAN for the wireless transmitting and receiving function, it is possible to implement a concise and low cost system which is highly versatile and capable of utilizing a most common infrastructure.