An electrical connector includes an insulative housing and a number of conductive contacts affixed to the insulative housing. The insulative housing includes a base portion and a tongue portion extending forwardly from the base portion. The tongue portion has a stepped portion abutting with the base portion, a horizontal portion located at a front end of the stepped portion, and a boundary line located between the stepped portion and the horizontal portion. The stepped portion is thicker than the horizontal portion. The horizontal portion has two opposite mating surfaces. Each conductive contact has a contacting portion exposed to the mating surface, a connecting portion affixed to the stepped portion and the base portion, and a soldering portion extending outwardly from the base portion. The contacting portion abutting with the boundary line is covered by insulative materials.