A card connector has a first receiving slot for receiving a first card and a second receiving slot for receiving a second card having a thickness smaller than the first card. A stopper member is supported in the first receiving slot by a supporting shaft and pivots between a first position where the stopper member blocks the first receiving slot to prevent advancement of the first or second card and a second position where the first receiving slot is unblocked. A cam member is pivotally supported in the card receiving slot by a supporting shaft arranged perpendicular to the supporting shaft of the stopper member and has a claw that abuts the stopper member to prevent the stopper member from pivoting to the second position. The cam member has a cam surface that releases the claw from the stopper member when the cam surface is cam-engaged by the first card.