To provide a communication system for medical image information using a portable communication terminal with which the medical image information is properly transmitted to a medical doctor at any place and the doctor who has obtained it quickly makes proper determination from the information and instructs treatment to a hospital.

First, a medical image is converted to digital information. Next, the image is converted to have a format and an image size proper to a portable communication terminal of the doctor, and thereafter, it is transmitted as a mail to a cellular phone set or stored in an image server to allow the doctor receiving the mail to download this medical image. Thus, the doctor speedily receives the medical image information at any place, quickly makes the determination from the obtained information, and instructs starting of speedy and proper treatment at the hospital to a patient in emergency and a patient whose condition is changed suddenly in the hospital.