To provide a technique capable of adjusting a tilt angle of a ship propulsion machine body with respect to a hull to a tilt angle suitable for a travelling state easily and with high accuracy. Mirror image shim coils can be connected in series in a symmetric sense or connected in series in a antisymmetric sense. The heat dissipation device includes a centrifugal fan defining an air outlet for airflow out, a heat sink arranged at the air outlet, and a heat pipe.