To provide an information provision system in a mobile body capable of enhancing usability by obtaining information even outside a mobile communication network and capable of solving a problem of a conventional information provision service using a portable terminal including that information can not be provided outside the mobile communication network, for example in a tunnel, subway and the like, because connection to a site can not be established.

In the information provision system in the mobile body, a central control unit 1 monitors operational situation of each train and creates data of operational situation for each train and sends the data to each train. An on-board information transmission device 2 for controlling radio communication in the train stores the received data of operational situation and connects with a portable terminal 3 through a communication network at the time when a specific access point number is called. Then, requested data are read and converted in HTML format and output for displaying on the portable terminal 3.