A radio frequency semiconductor device package includes a metal base plate, a first metal wall, a second metal wall, and feed-through parts. The first metal wall is provided with first and second openings and connected onto the metal base plate. The openings are set back from a lower surface side and do not reach an upper surface. The second metal wall is connected to the upper surface of the first metal wall. Thickness of the second metal wall is larger than thickness of the first metal wall. The feed-through parts include insulators and line patterns insulated from the first and second metal walls and are joined to inner walls of the openings and the metal base plate.