A card device includes a card casing accommodating a circuit board. The card device is capable of being inserted into and pulled out from a card slot in an apparatus in which the card device is to be mounted. An anti-slipping member is anchored and exposed at a rear-end wall portion of a peripheral wall of the card casing for being held at least when the card device is inserted or pulled out. The rear-end wall portion is positioned at a rear end of the card device opposite to the end of the card device that is inserted into the card slot.