Heat generating element housing device

A heat generating element housing device includes a first side surface, a second side surface, a first shelf plate, second shelf plates, module cases, and highly heat conductive members. The module cases are in a substantially rectangular parallelepiped shape and are fixed to the second shelf plates at the respective heights, with their longitudinal direction directed along a flow direction of the air. Each of the highly heat conductive members is fixed, with its heat transfer surface being in contact with at least one of the longitudinal side surfaces of the module case and with a side portion of the heat transfer surface being in contact with the second shelf plate.