An electronic component housing package includes a base body made of a metal; a rectangular frame body made of a metal; an input/output terminal made of insulating material, which has line conductor for electrically conductively connecting the interior and exterior of the frame body; and an input/output terminal mounting portion, into which input/output terminal is fitted and which is formed as a notch extending across two adjacent corners of a frame body's lower part. The input/output terminal is so configured that its opposed end-face pair at two corners are made flush with opposed outer-side-surface pair including two corners of frame body, and that metal layer is applied to both of a part of an input/output terminal's end-face extending along the mounting portion and another part thereof extending along the base body.