A triplate line inter-layer connector and a planar array antenna are provided. The triplate line inter-layer connector has an electrical connection structure between a first triplate line and a second triplate line, a first patch pattern formed at a connection-side terminal end of a first feeder line, a first feed substrate having a first shield spacer disposed therebeneath, and a second shield spacer disposed thereabove. Each of the first and second shield spacers has a hollow portion hollowed out to a size encompassing the first feeder line and the first patch pattern so as to define a corresponding one of first and second dielectrics. A second feeder line is provided on a second feed substrate together with a second patch pattern, and a second ground conductor has a first slit formed in a portion thereof located approximately intermediate between the first and second patch patterns.