The washing apparatus has a frame body 18 to be filled with a cleaning liquid. The frame body 18 is rotated within a casing by a drive motor 23. The frame body 18 has an inner periphery having a wavy patterned surface. An inner diameter D of the frame body 18 is set to more than or equal to 600 mm and less than or equal to 850 mm. The frame body 18 is rotated so that a peripheral speed of the inner periphery 39 is more than or equal to 28 m/min and less than or equal to 57 m/min. A height h of the wave form is set to more than or equal to 2.0% and less than or equal to 9.0% of the inner diameter D, and a pitch p of the wave form is set to more than or equal to 2.0% and less than or equal to 9.0% of a peripheral length L of an imaginary circle having a diameter of the inner diameter D.