An automatic card shuffler includes two parallel stands, two conveying units respectively mounted in the stands for conveying playing cards out of the associating stands toward a space between the stands, two limiters respectively mounted in the stands for holding playing cards for delivery by the conveying units individually, a card carrier unit set between the stands and controllable to lift a holder plate for collecting playing cards delivered from the conveying units, a constraint mechanism set between the stands for holding playing cards on the holder plate in a stack, and a card dispensing mechanism disposed above the stands for pushing playing cards out of the holder plate of the card carrier unit toward the baffles of the limiters in the working spaces of the stands alternatively.