To selectively use a highly heat-conductive material for improving heat dissipation to cope with heat generation from an electronic element such as a semiconductor chip so as to prevent degradation in efficiency and improve an output.

A package matrix body 30 of an electronic component package consists of a plurality of package bodies 31 placed in a matrix on an insulating base member 34. A metallic heat-dissipating member having anisotropic heat conductivity is mounted as a heat radiator 39 on the rear of the package matrix body 30 to constitute the electronic component package. The metallic heat-dissipating member of the heat radiator 39 is placed while the direction of the high heat conductivity is aligned with the vertical direction of the package body to improve heat dissipation and make its horizontal direction as the direction of low heat conductivity. In addition, a heat conduction shielding groove 40 is formed in the lateral (y-axis) direction to prevent heat transfer at the border between the package bodies 31.