To reduce damage inflicted on an object to be washed in a washing process for scrub-washing the object to be washed simultaneously from both front and rear sides.
A pair of brush rollers 1A, 1B are insert-fitted to two rotating shafts respectively. In a cross section that includes the axes of the two rotating shafts almost orthogonally to the rotating direction of the two rotating shafts, the respective base end portions of a plurality of first protrusions 5A contacting a first washed surface 11A are projected to the object 10 to be washed from a direction substantially perpendicular to the first washed surface 11A to form a plurality of first regions La, and the respective base end portions of a plurality of second protrusions 5B contacting a second washed surface 11B are projected to the object 10 to be washed from a direction substantially perpendicular to the second washed surface 11B to form a plurality of second regions Lb. A plurality of overlap ranges Lp where the plurality of first regions La and the plurality of second regions Lb overlap are limited to a range of 80% or less to either of the first regions La and the second regions Lb including the overlap regions Lp regardless of the rotating positions of the two brush rollers 1A, 1B.
ITO CHIZURU
SAITO TAKAHITO
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