The shell-and-tube heat exchangers mentioned in this paper are the typical types of heat exchangers. We divide them into four classes, on the basis of the fluid condition. That is, (1) one fluid condenses and the other vaporizes, (2) one fluid condenses and the other does not change its phase upon heating, (3) one fluid vaporizes and the other does not change its phase upon cooling, and (4) neither fluid changes its phase upon heat-exchange. In this paper, the dynamic characteristics of the four types of shell-and-tube heat exchangers mentioned above are investigated experimentally and theoretically. In the theoretical study, the dynamic characteristics were investigated from the viewpoint of the network theory. As a result, a very simple network model was derived. It is shown that this model is adaptable for all types of shell-and-tube heat exchangers regardless of the operational condition and the kind of fluids in the heat exchanger. The validity of the model was proven by comparison with the experimental results.