As a part of study on the diffusion control of jet flow, the purpose of this study is to control the jet diffusion by using the deforming nozzle. The shape of polypropylene nozzle can change from square shape into cruciform one smoothly. The velocity measurement of the jet flow was performed using a hot-wire anemometer, by changing the shape of nozzle variously. The basic characteristics of the jet flow, such as velocity distributions and half value widths have been obtained. As a result, it has been clarified that the jet width in xOy'-plane is large, comparing with that in xOz-plane. Moreover it has been also found that the effect of deforming of the nozzle on jet diffusion is appeared in xOy'-plane.