The similitude of a movable-bed model was discussed based on the comparison of the data of model tests with the field data for the case of Kashima Port. The model tests were conducted from January to July in 1967, and were made of several existing or scheduled conditions of the construction of breakwaters and dredging of
the navigational channel in Kashima Port from June 1965 to August 1968.
　The model was made with the sand of 0.2mm in diameter in an out-door basin of 50cm long, 30cm wide, and 80cm deep with the scale of 1:200 in horizontal and 1:40 in vertical. It was concluded that the similarity of the variation of the depth contour lines was reasonablly acceptable except for some portion along the breakwaters, however, the variation of the volume of sand in the harbour was not successfully simulated.