The heat dissipation device and a semiconductor device

In a laminating direction of first to fifth ceramic sheets (21, 22, 23, 24, 25), a first slit (22c) and a second slit (22d) are positioned closer to a first mounting section (121) and a second mounting section (131) than a first communication hole (23c), a second communication hole (23d), a third communication hole (23e) and a fourth communication hole (23f). Moreover, an overlapping section (35) where the first slit (22c) and the first communication hole (23c) overlap, and an overlapping section (36) where the second slit (22d) and the third communication hole (23e) overlap, are positioned in the vicinity of an area where the first mounting section (121) and the second mounting section (131) are disposed when viewed from the laminating direction of the first to fifth ceramic sheets (21, 22, 23, 24, 25).