An electric connector includes an insulative body and groups of contacts. The contacts are disposed in spaced relationship inside the body and arranged in at least two rows in a lateral direction of the body. The groups of contacts include a plurality of first contacts; and a plurality of second contacts located in a different row from a row where their associated first contacts exist, the second contacts being arranged next to the first contacts. Out of one of the first contacts and one of the second contacts subject to impedance tuning, one of these two contacts has a width and an area thereof adjusted in accordance with a difference in impedance from impedances between other first and second contacts.