A feedthrough-capacitor unit provided with a plurality of feedthrough-capacitors, including a plate made of synthetic resin, a plurality of projections which are provided on one face of the plate and are each formed with each of a plurality of first through-holes, a plurality of terminals which are mounted on the plate so as to extend through the first through-holes, respectively and a plurality of capacitor bodies which are each formed with each of a plurality of second through-holes such that the projections are, respectively, fitted into the second through-holes.