Characteristics of cargo flow between a port and its hinterland are analyzed quantitativelty at major ports in three major bay regions, Tokyo Ise, and Osaka bay, in 1982 and 1992.
　In this paper, we attempt to measure the actual distance and time of cargo flow, with developing the new numerical calculation method. As fundmental data, both the data base on domestic transportation system (Natinal Land Agency) and the survey on the land transport flow of port cargo (Ministry of Transport) are employed.
　Results of this study are summarized as follows;
1. The port cargo of three major bay regions flows more than 2,000 kms in distance and 20 hrs in time.
2. The average distance of cargo flow is 30 kms. The convensional cargo flows about 25 kms, and the container cargo more than 110 kms, resepectively. Generally speaking, these distances is increasing in the recent 10 years.
3. The rate of cargo flow at a certain distance varies inversely with nearly the second power of that distance, especially to 700 kms. Alomst the same relation is also observed for the case of time of cargo flow, especially to 10 hrs. The correlation to time is a little stronger than that to distance.