SPEED CONTROL DEVICE, AUTOMATIC NAVIGATION SYSTEM, AND SPEED CONTROL METHOD

A speed control device which is satisfactory in response and tracking to a speed setting, and can adjust an acceleration-and-deceleration feel according to preferences, is provided. The speed control device 6 controls a speed of a ship so that the speed automatically follows a speed setting set by a ship operator. The speed control device 6 includes a target speed setting module 63 and a change rate adjusting module 64. The target speed setting module 63 sets a target speed that is a target of the speed of the ship to follow, for every unit time, according to the speed setting, to change the target speed based on a given rate of change. The change rate adjusting module 64 decreases the rate of change by adjusting the rate of change at multiple stages, when the target speed set by the target speed setting module 63 approaches the speed setting.