Noncontact micro manipulation technique is needed in micromachine technology, biotechnology and so on. In the present paper, a standing wave field is generated in a microchannel, it is possible to trap small objects at nodes of the sound pressure distribution in the medium. A microchannel of 1mm × 50 mm × 1mm was made at the center of a glass plate of 50 mm × 50 mm × 5mm. In the experiment, when the liquid water containing alumina particles was injected into the microchannel on glass plate irradiated by ultrasound, the particles flowed along several layers. It was shown that the traveling wave was transmitted into the microchannel and the standing wave field was formed in the microchannel. Moreover, when the frequency of the ultrasound was swept, the particles were spatially shifted. It was able to control the direction of the particle flow by changing the ultrasound frequency in the branched microchannels. Copyright © (2010) by the International Congress on Acoustics.