A connector having juxtaposed contact modules (6). In each contact module, signal contacts (16), a first ground plate (14), and a second ground plate (15) are held by an insulator (28). The first and second ground plates comprise plate sections (14a, 15a) each having a first surface and a second surface on the opposite side of the first surface, and the first surfaces face each other. Pairs of protrusions (14b, 15b) are formed at intervals on the second surfaces of the plate sections. The first and second ground plates are molded in the insulator and integrated together. The insulator has recesses (29) corresponding to the intervals of the protrusions and signal contacts are disposed in the recesses.