FIGS. 11A and 11B are views showing a high frequency package according to still another embodiment of the invention, in which FIG. 11A is a plan view, and FIG. 11B is a sectional view taken along line IX-IX of FIG. 11A. In FIGS. 11A and 11B, reference numeral 120 denotes a high frequency electronic component; reference numeral 121 denotes a mounting part; 122 reference numeral denotes a metal base