the process control means 8 sets the water level within the hold 1 to a medium level when under this situation the user of the washing machine manipulates the water level setting means 9a to set the water level to a high level by the reason that he or she had considered that the medium level of water is insufficient for the actual amount of the cloths the determining means 12 responding to the change in water level setting adds a predetermined number of waveforms u03b4pa to each of the reference values p 1 p 2 and p 3 to thereby shift the respective reference value to a higher value as shown by the following equations these shifted reference values are utilized subsequently for the determination of the amount of cloths put into the washtub 1 thus consequent on the change of the reference values the amount of cloths determined by the determining means 12 increases on the other hand in the case of the situation substantially reverse to that discussed above that is when the user of the washing machine manipulates the water level setting means 9a to set the water level within the hold 1 to a medium level under the situation in which the determining means 12 has determined that the amount of cloths put into the washtub 1 was 34 maximum 34 and hence the process control means 8 has set the water level within the hold 1 to a 34 high 34 level the determining means 12 responds to the change in water level setting in such a way as to subtract a predetermined number of waveforms u03b4pa from each.