A semiconductor memory device includes a housing having a wall, a circuit board located in the housing and spaced from the wall and extending along the surface of the wall, a memory located on the circuit board, a heat conduction member interposed, and compressed, between the wall and the memory. The wall includes an uneven region comprising contact portions contacting the heat conduction member and recess portions located between the contact portions. The recess portions are recessed inwardly of the wall from the ends of the contact portions in a direction away from the location of the memory.