Indoor unit and refrigeration cycle apparatus

An indoor unit comprising:

• a main unit including an air inlet through which air enters from a room and an air outlet through which air blows into the room;
• an electrical component box mounted on an outer surface of the main unit and accommodating an electrical device;
• a refrigerant pipe connection portion to which a refrigerant pipe is connected and through which refrigerant passes;
• a drain pipe connection portion to which a drain pipe is connected and through which drain water is discharged from the main unit;
• installation bolt attachment brackets mounted on the outer surface of the main unit and fixing the main unit to installation bolts suspended from above a ceiling, the installation bolt attachment brackets extending outwardly and perpendicularly from sides of the main unit, and a same mounting surface mounting the refrigerant pipe connection portion, the drain pipe connection portion and the electrical component;
• the same mounting surface being a planar surface extending parallel to the installation bolts and being located beyond tip portions of the installation bolt attachment brackets, wherein the drain pipe connection portion is mounted on the same mounting surface away from and outside of the electric component box, and wherein the indoor unit is embedded in the ceiling of the room, is a four-way cassette structure and has the air outlets facing in four directions and the air inlet, the air outlets and the air inlet facing an interior of the room.