A differential signal connector includes a plurality of pairs of signal contacts, a plurality of ground contacts, and an insulating housing holding the signal contacts and the ground contacts. On a first connection side for connection to a connection partner, the ground contacts are arranged on both sides of each pair of signal contacts so that a contact array of a fixed pitch is formed. On a second connection side for connection to board, the ground contacts are arranged spaced apart from each other in a first row, while the pairs of signal contacts, which are adjacently arranged on both sides of the ground contact on the first connection side, are arranged so as to be allocated in a second row and a third row located on both sides of the first row so that the pairs of signal contacts are arranged zigzag on the second connection side.