To make it possible to package a three-dimensional highly concentrated head radiator by forming an air flow where a cooling air injected from a tip of a nozzle is collided to an opposedly located heat radiation substrate and released outside through a gap between an external circumference of the nozzle and the heat radiation substrate.

A heat radiation substrate polyhedron 11 opens a side plate comprising a heat radiation substrate 12 as a bottom plate and heat radiation substrates 13a to 13b as side plates, and a nozzle 15 is inserted for cooling air injection. The nozzle 15 connected to a blower and the like through piping feeds a cooling air into the heat radiation substrate polyhedron 11, collides the cooling air to the heat radiation substrate 12, and releases the air from the opening by flowing it through a path 17 sandwiched by the heat radiation substrate 13a to 13d and the nozzle 15. The cooling air flow forcibly cools an inner surface of the heat radiation substrate 13a to 13d heated by conduction from LSI packages 14b and 14c.