A particle removal device includes: a stage on which a target substrate is disposed; an inner case defining a first discharge opening through which the stage is exposed to an internal space of the inner case; an outer case including: a side wall portion surrounding the inner case, a protrusion portion protruded from the side wall portion toward the inner case, and a second discharge opening in fluid connection with the first discharge opening; a suction pump connected to the second discharge opening; an air injector in fluid connection with the internal space; and an intake opening in fluid connection with the first and second discharge openings. A width of the intake opening as a distance between the distal end of the inner case and the distal end of the protrusion portion is smaller than a width of the first discharge opening.