There are some sea areas where the upwelling current rises from sea bottom up to sea surface and brings the deep sea water including a plenty of nutritive salts accumulated on the sea bottom up to the sunny sea surface. Such sea areas are well known to be rich fishing grounds. Therefore, in order to make rich fishing ground artificially, various kinds of marine structures for generating the upwelling current are studied. At the same time, it is important to evaluate the influence on local ocean environment by such artificial ocean fertilization. The purpose of the present study is to investigate the scale effect on the vortical flow induced by artificial upwelling structure in order to evaluate an effectiveness of a full-scale upwelling generator from the model test results. The type of upwelling generator adopted in this study is basically a V-shaped structure placed against to the horizontal bottom flow. The V-shaped structure consists of two long flat plates which are connected with each other with a dihedral angle, and the top view is as a letter of V with its vertical angle directing downstream. By use of two geometrical similar models of V-shaped structure with different sizes, flow visualization tests and velocity measurements in their wake were carried out. The Reynolds number based on uniform flow velocity and model height is in range from 3900 to 67200. The vorticity distributions at two vertical planes in downstream of the models were obtained from the measured results. It is shown that non-dimensional vorticity of the center of vortices produced by V-shaped structure models increases slightly with model size. On the other hand, theoretical consideration was made on the scale effect of the above vortical flow. An approximate equation was introduced for estimation of Reynolds number effect on the vorticity. According to the equation, the non-dimensional vorticity of the vortices produced by the V-shaped structure is proportional to Reynolds number to the one tenth. It is found that this estimation agrees well with the results of measurements.