The present invention relates to a laundry processing apparatus comprising: a tub for storing water and provided with an opening for putting in and taking out laundry; a drum, provided in the interior of the tub, for storing the laundry supplied through the opening; an agitator rotatably provided inside the drum; a rotating shaft connected to the agitator by penetrating the tub and drum; a driving part for rotating the rotating shaft; a connecting part having a connecting body fixed to the drum, and a body-penetrating hole which is provided so as to penetrate the connecting body and through which the rotating shaft is inserted; and a power transmission part, provided inside the body-penetrating hole and connecting the rotating shaft and connecting body, for transmitting the driving power provided by the rotating shaft to the connecting body only when the rotating shaft is rotating in either the clock-wise direction or counter-clock-wise direction.