Abstract: A weighing machine, such as a combinational weighing machine, has scale cells and a plurality of dummy cells installed on the same floor. The scale cells output weight signals corresponding to the weights of objects being loaded. The mode of vibrations of the floor is detected from dummy signals from the dummy cells, vertical displacements of the floor at the positions of the scale cells are calculated, and their effects are eliminated from the weight signals. Those of the scale cells not selected after a cycle of combinational calculations can be used as dummy cells in the next cycle. A memory device may be provided to store preferred combinations of such scale cells not selected that may be used for this purpose. Effects of the floor vibrations can be eliminated more accurately if the differences in sensitivity among the cells due to physical characteristics of the individual cells and/or due to the different loads on them can be taken into account either by a feedback calculation or by a formula.