An apparatus for treating laundry includes a tub, a drum, a motor configured to rotate the drum, a rotation shaft coupled to the motor, a first body including a first body hub located at a rotational center of the drum and fixed to the drum and a first body arm extended from the first body hub toward an edge of the drum, a second body including a second body hub located in the tub and fixed to the rotation shaft and a second body arm extended from the second body hub toward the first body arm, a connecting part connecting the first body to the second body and defining a space between the first body and the second body, and a reinforcement rib extended from the connecting part along the first body arm to connect the connecting part to the first body arm or the second body arm.