To provide a raft houseboat for performing undersea observation on board while moving over the sea and performing diving or snorkeling after arriving at a diving spot, which is provided with an undersea observation transparent window allowing on-board underwater observation in the marine area and has a self-traveling function mounted with a submersible device using photovoltaic power generation or wind power generation.

In the raft houseboat, a floor surface 5 is constructed around an undersea observation box 1 provided with the undersea observation window 2 at the bottom, the observation box having an area such that a plurality of persons can be simultaneously seated, and a floating body (foam polystyrene) 14 is housed under the floor surface to secure the buoyancy of the rafting houseboat. A roof 8 covered with a photovoltaic generation panel 9 is constructed over the whole surface of the floor surface, a cylindrical wind power generator 12 is installed below an eaves of the roof to perform private electric generation, and the submersible device and a portable toilet are arranged at a corner of the buoyancy housing space.