A high-pressure homogenizer is provided in which a cleaning water is introduced by a simple operation and a feed-holding hole part can be easily cleaned without fail without the need of disassembling/assembling a pressure-elevating mechanism part. The homogenizer is hygienic and is excellent in maintenance and management. The fine opening of the orifice of the high-pressure homogenizer can be easily secured without fail. The homogenizer contributes to the pulverization and high-pressure homogenization of a raw material. The homogenizer comprises: a high-pressure homogenization mechanism part (1) in which a suspension (2) or semisolid (2') containing a raw material (G) is passed through an orifice (3) to pulverize or otherwise treat the raw material; and a feed-holding passageway (8) connected to the part (1). One of a piston-receiving member (5) and a feed-treating piston (4) is moved relatively to the other, or the piston-receiving member and the feed-treating piston are moved relatively to each other. Thus, the volume of a feed-treating hole part (6) is reduced to thereby pump the suspension or semisolid and pulverize or otherwise treat the raw material. When the feed-treating piston is moved back to or beyond a position (6a) around an open end of the feed-treating hole part, a cleaning liquid (W) is introduced into the feed-holding hole part to clean it.