PURPOSE: To wash a root of a "wasabi" (a Japanese horseradish) efficiently, by means of plural protruded washing brushes driven by a motor in a washing box.

CONSTITUTION: A root (R) of a "wasabi" (a Japanese horseradish) is inserted from a circular hole (C) of a washing box 3 and rubbed by washing brushes 8, 9 and 10 rotated by the driving of a motor 7 in the same direction and simultaneously sprayed with washing water from spaying holes 16 of a water spraying pipe 5. Thus, the mud, sand, remaining hairy roots, black epidermis (skin), etc. sticking to the surface of the "wasabi" root (R) are removed to luster the surface of the root (R).