PURPOSE: To attain to enhance workability and the reliability of a metered value, by displaying class signal judged through the comparison with a set reference wt. along with wt. display after a scale is brought to a stable state.

CONSTITUTION: The load on a scale 1a is detected by a load detecting part 1 and the detected value is outputted while subjected to digital conversion at every predetermined time to be sampled in a control part 2. The control part 2 is constituted of CPU21 for performing various kinds of operations, a program and control, ROM 22, RAM23 and a clasifying reference wt. memory group 24 and these elements are mutually connected by bus lines. In addition, a keyboard 3 equipped with ten keys and an operation key, a digital display device 4 and an output port 5 are connected to the control part 2 and, when the sampling data of the specimen on the scale 1a reaches a stable state, the class signal of the memory 24 is displayed by the display device 4 along with the wt. value thereof.