A signal transmission device includes: a first substrate and a second substrate; a first resonance section including a first resonator and a second resonator electromagnetically coupled to each other; a second resonance section disposed side-by-side relative to the first resonance section, and electromagnetically coupled to the first resonance section to perform a signal transmission between the first and second resonance sections; and a first shielding electrode disposed between the first resonator and the second substrate and partially covering the first resonator to allow at least an open end of the first resonator to be covered therewith, and a second shielding electrode disposed between the second resonator and the first substrate and partially covering the second resonator to allow at least an open end of the second resonator to be covered therewith.