PURPOSE: To provide a weighing and classifying device surely weighing fishes and shellfishes such as a scallop to classify the same with good maintenance.

CONSTITUTION: Three weighing plates 107 are arranged so as to provide an interval therebetween and the receiving part T receiving the scallop M supplied from the scallop chain belt conveyor 78 provided above the weighing plates is formed and the load cell 111 weighing the scallop M on the receiving part T is arranged to the upper part. Three discharge plates 114 arranged so as to be capable of passing through the gaps between the weighing plates 107 are driven by a crank mechanism and, when the discharge plates 114 pass through the gaps during the driving process, the scallop M weighed in the receiving part T is pressed to be supplied to each of buckets 35 from the receiving part T. The buckets 35 are pivotally supported on the chains of a chain conveyor 32 in a freely rotatable manner and inclined at each area by measured wts. during feed by a control unit not shown in the drawing to classify the scallop M to discharge the same.