Wiring board, electronic device, and electronic module

A wiring board comprising:

• an insulation substrate having a first surface, a second surface located on an opposite side of the first surface, and a recessed portion opened on the second surface, the insulation substrate having a rectangular shape in a plan view;
• an external electrode located on the first surface;
• and
• a connection electrode located on a bottom surface of the recessed portion,
• wherein the external electrode comprises
• a first external electrode and a third external electrode located at opposing corner portions along a first diagonal line of the first surface and electrically connected to the connection electrode, and
• a second external electrode and a fourth external electrode located at opposing corner portions along a second diagonal line of the first surface,
• the second external electrode and the fourth external electrode being connected by a connection wiring located inside the insulation substrate and comprising a portion inclined with respect to the first surface,
• the wiring board further comprises
• a first through-hole conductor at least partially overlapping the first external electrode in a plane perspective and extending toward the bottom surface from the first surface, and
• a second through-hole conductor at least partially overlapping the third external electrode in a plane perspective and extending toward the bottom surface from the first surface, and the connection electrode comprises
• a first connection electrode connected to the first external electrode via the first through-hole conductor, and
• a second connection electrode connected to the third external electrode via the second through-hole conductor,
• the first connection electrode and the second connection electrode being located at positions of point symmetry with respect to a center of the second surface.