A particle dispersion method for dispersing particles (500) fixed on the inner surface of a container (12) into a liquid. The particle dispersion method includes a discharge step of discharging a liquid into the container (12). The container (12) has a cylindrical main body part (310), and an inclined part (311) having an inner diameter that decreases from the main body part (310) side to the bottom part side and having a constant angle relative to the central axis of the container. In the discharge step, the liquid is discharged from above the inclined part (311) toward the inclined part (311) on the side opposite the particles (500) fixed to the inner surface of the container (12) across the central axis (300) of the container (12).