An electrical connector includes an insulating housing and a plurality of electrical terminals. A top face of the insulating housing is concaved downward to define a plurality of terminal grooves alternately arranged into two rows along two longitudinal sides of the insulating housing. Each terminal groove extends transversely to have the outer end thereof penetrate through a corresponding side face of the insulating housing. The inner ends of the two rows of terminal grooves are alternate with one another along a substantial longitudinal middle of the insulating housing. The electrical terminals are firstly assembled downward and then pushed transversely inward to be assembled in the terminal grooves respectively.