Abstract: A card connector comprises an insulating housing (1), at least a first set of contacts (2) and a second set of contacts (3) retained in the insulating housing (1) and a defend mechanism (6); the insulating housing (1) defines a card receiving space with a card inserting direction; the defend mechanism (6) disposes in the housing and comprising a step portion protruding into the card receiving space and a restorable portion extending from the step portion; the step portion divides the card receiving space into at least two card cavities according to external dimensions of the different cards and deflects between the two card cavities and protruding into one card cavity once a card inserted into the other card cavity; the restorable portion for urging the step portion to resume its original position once the card withdrew from the other cavity.