To provide a propulsion device of a vessel capable of preventing damage to a propeller caused by contact with driftage such as ice.

This propulsion device is provided with a main engine 4 for generating a rotational driving force, the propeller 6 rotated and driven by the main engine 4, a detecting part 7 for detecting the contact of the propeller 6 with the driftage, and a control part 8 for controlling the number of rotations of at least the main engine 4 based on a detection result of the detecting part 7.