Insulator, and electrical connector and connector assembly using insulator

The invention relates to an insulator, and an electrical connector and a connector assembly using the insulator. The insulator of the electrical connector comprises an insulator body, wherein at least two contact element installation holes provided with axial lines extending along the forward and backward direction and respectively used for installing corresponding contact elements are formed in the insulator body; an insulating cell is arranged between each two adjacent contact element installation holes at the rear end of the insulator body. The insulating cell is arranged on the insulator, and the creepage distance between conductor jointing ends of each two adjacent contact elements is increased, so that the distance between the two contact elements can be reduced, and the structure size of a whole product is reduced.