In a laminating direction of first to fifth ceramic sheets, a first slit and a second slit are positioned closer to a first mounting section and a second mounting section than a first communication hole, a second communication hole, a third communication hole and a fourth communication hole. Moreover, an overlapping section where each first slit and the first communication hole overlap, and an overlapping section where each second slit and the third communication hole overlap, are positioned in the vicinity of an area where the first mounting section and the second mounting section are disposed when viewed from the laminating direction of the first to fifth ceramic sheets.