A dispersing and grinding device for dispersing or grinding particles in a particle-containing liquid with a shear force generated when the particle-containing liquid passes through a gap, the dispersing and grinding device including: a casing; a rotor, a stator, and an impeller; and drive means. The gap is defined between the stator and the rotor. When the rotor and the impeller are rotated by the drive means, the particle-containing liquid is allowed to flow into the casing through an inflow portion of the casing by a rotating force of the impeller, and passes through the gap to cause the particles in the particle-containing liquid to be dispersed or ground with a shear force generated when the particle-containing liquid passes through the gap.