There are many papers regarding with calculation of characteristic value of reinforced rectangular plate in vibration, but in actual calculation we have such trouble as follows ; (1) it is very difficult to calculate in case of many reinforements (2) most papers can not be used for various boundary conditions of the plate, especially for elastic built-in edges. (3) most papers can not be used for various end conditions of reinforcements, especially in case of end blacket of reinforcements. (4) it is very difficult to calculate in case of high order frequency. (5) most papers do not consider torsional rigidity of reinforcements. In this paper, the author removed the above troubles by means of the calculation by electric computer, based on the program of theoretical method which is published already in this society.