A card connector is adapted for being mounted to a circuit board defining a mounting cavity. The card connector includes an insulating housing defining a receiving room passing through a top and a front thereof, a plurality of electrical terminals disposed in the insulating housing and electrically projecting upward into the receiving room, a shielding shell enclosing the insulating housing, and a plurality of fastening blocks. A pair of side walls is formed at two opposite sides of the receiving room. The fastening blocks are apart secured to outsides of the side walls. The card connector is mounted in the mounting cavity of the circuit board, and the fastening blocks are fixed on the circuit board around the mounting cavity. Because the fastening blocks are not easily deformed, the card connector can be firmly fixed in the circuit board and avoids being slanted downward in use.