A solid-state drive device includes a first module including a first region containing a volatile main memory device and a controller device and a second region containing a first nonvolatile memory device, a second module disposed on the first module and having a third region containing a second nonvolatile memory device, the second module being connected to the first module, and a heat dissipating member disposed on the second module as vertically juxtaposed with the first and second modules. The heat dissipating member has a protruding portion protruding toward the first module and in direct thermal contact with the first region, and a plate-shaped portion having a main surface in direct thermal contact with the third region.