Boat propulsion device and boat

A boat propulsion device comprising:

• a cowl;
• an upper case below the cowl in a first direction;
• a lower case below the upper case in the first direction and rotatable about a steering shaft extending in the first direction relative to the upper case;
• an engine in the cowl;
• a propeller shaft supported by the lower case;
• a drive transmission in the upper case and the lower case and configured to selectively execute a first transmission state in which the propeller shaft is rotatable in a first rotational direction, and a second transmission state in which the propeller shaft is rotatable in a second rotational direction opposite to the first rotational direction;
• an electric actuator in the cowl and including a rotating output shaft;
• and
• a shifter in the upper case configured to switch the drive transmission between the first transmission state and the second transmission state in accordance with rotation of the output shaft of the actuator.