To efficiently eject outside a heat generated by electrical parts packaged in a substrate without any excessive enlargement and enormous weighting of an outdoor installed apparatus and further any consumption of a useless electric power.

The heat generated from the electrical parts packaged in the substrate is efficiently ejected in an atmosphere by such a configuration as to seal a substrate projecting outside from a main body 3 with an exterior package body 2 having a thermal conductivity and a weatherproof, and as to mount the substrate itself in the state of projecting the substrate itself outside from the main body 3. Consequently, forced cooling means such as a heat exchanger, a fan or the like is made unnecessary, and the apparatus can eliminate the enlargement and enormous weighting of an outdoor communication apparatus (outdoor installed apparatus)1, and further a consumption of a useless electric power required for driving the fan.