A chamber for exerting an ultrasound beam on a sample solution containing particles to be concentrated, separated or arranged is provided with a view toward arbitrarily controlling the shape of a spatial distribution of potential energy created by the ultrasound beam and concentrating, separating or periodically arranging the particles. In contrast to the chamber, irradiation ultrasound sources for generating ultrasound beams are provided to create an ultrasonic intensity distribution for producing a position potential energy distribution used to exert a force forwarded in a predetermined direction or a force staying at a predetermined region to each particle. Thus, a specific spatial distribution of potential energy can be realized by ultrasound beams each having a specific intensity, a specific frequency and a specific phase or an ultrasound beam formed by superimposing these on one another. Further, at least one suction hole for recovering separated solvents or particles is defined in a wall surface of the tube, which is orthogonal to the flow of the sample solution.