PURPOSE: To make it possible to obtain an energy saving ship, by providing such arrangement that a ship attitude computer is provided to compute the angle of pitching, the angle of rolling, a draft, etc. with which the fuel consumption of the ship is minimum in accordance with detected values from the cargo- loading condition and course detectors to control the attitude of the ship.

CONSTITUTION: There are provided a loading data processing unit 2 for detecting the cargo-loading condition of a ship, a course data processing unit 3 for detecting course data, and a fuel-consumption computer 4 for computing fuel- consumption. There is provided a ship attitude computer 1 which receives data through a data bus 8 from all of the loading data processing unit 2, the course data processing unit 3 and the fuel-consumption computer 4 and then calculates the attitude of the ship, that is, the angle of pitching, the angle of rolling and a draft, in which attitude the fuel consumption of the ship may be minimum. The control of attitude in accordance with the condition of cargo-loading can be made in each sailing.