A card holding member able to be inserted into a card connector via an insertion slot in an outer member and able to hold a card equipped with terminal members, the card holding member comprising a card accommodating portion able to accommodate the card, a connecting base portion connected to the card accommodating portion, a movable sleeve mounted on the connecting base portion slidably in the insertion and ejection directions of the card holding member, a first sealing member forming a seal between the connecting base portion and the movable sleeve, and a second sealing member forming a seal between the insertion slot and the movable sleeve. The use of the two sealing members helps to absorb displacement of the card holding member in case of misalignment between the card connector and the insertion slot.