Manufacturing of the silicon carbide porous body was performed in a similar manner as example 1. However, through holes having a diameter of 9 mm were formed in the four corners of the molded body by machining after firing. In addition, after filling the formed through holes with aluminum short fibers similar to those employed in example 1, metal impregnation and machining similar to example 1 were performed, and heat-dissipating components were manufactured. Then, through holes having a diameter of 7.5 mm were formed in the portion formed by the aluminum short fibers and the impregnated metal. That is, in these comparative examples, the portion formed by the aluminum short fibers and the impregnated metal has a structure not forming a portion of the outer peripheral surface of the heat-dissipating component. For these heat-dissipating components, the same evaluation as that of example 1 was carried out. The results are shown in Table 1.

Aside from the fact that the notch portions of the four corners were not filled with the aluminum short fibers, the heat-dissipating components were manufactured in the same way as example 1. For these heat-dissipating components, the same evaluation as that of example 1 was carried out. The results are shown in Table 1.