Roof air vent device

A roof air vent device includes: a roof provided to cover an upper portion of a vehicle; a duct housing provided in the roof extending in a length direction or width direction of the vehicle to draw air into the duct housing; a guide member provided inside the duct housing in the extending direction of the duct housing to distribute the air drawn into the duct housing; and a rotating nozzle including a discharge unit provided to the duct housing to discharge the air drawn into the duct housing into a vehicle cabin and to change directions of air discharge by rotation of the discharge unit.