There is provided a filling method which is capable of suppressing uneven distribution of particle diameter and suppressing property decrease of the particulate water-absorbing agent. The method for filling the particulate water-absorbing agent according to the present invention includes a abutting step for making a member for filling the particulate water-absorbing agent abutted on a vibrator; a supplying step for supplying the particulate water-absorbing agent to the member for filling; and a vibration step for vibrating the particulate water-absorbing agent present in the member for filling by vibrating the vibrator. Preferably, the supplying step is performed by dividing into a plurality of times. Preferably, the vibration step includes an intermediate vibration step performed at a stage where a part of a plurality of times of the supplying steps is completed, and a final vibration step performed at a stage where all of a plurality of times of the supplying steps is completed. Total filling mass W2 is set preferably at 500 kg to 1500 kg.