Abstract: The cleaning treatment apparatus of the present invention is constituted so that a cleaning liquid is continuously supplied by a liquid film forming means in a gap formed between a surface of a processed member held horizontally and rotationally driven by a holding and rotating means and a ultrasonically oscillating lower face of a ultrasonic oscillating means, to thereby form a liquid film in the gap. Hereby, the surface of the processed member is subjected to a cleaning treatment by the liquid film, which is ultrasonically oscillated by the ultrasonic oscillating means. At this stage, as the processed member is rotated by the holding and rotating means, the surface of the processed member is properly cleaned by the ultrasonically oscillating cleaning liquid not only in a region thereof opposed to the ultrasonic oscillating means during the standstill of the member but also in a region thereof opposed to the ultrasonic oscillating means during the rotation of the member.