Combination weiching apparatus

A combination weighing apparatus has weighing buckets (33) to weigh masses of material and subsequently transfer them to auxiliary buckets (36) for temporary storage, the masses in the weighing buckets (33) and/or in the auxiliary buckets (36) being selected in combination processing and then discharged to forming a batch of predetermined weight. The apparatus comprises: a first detecting means (1) detecting a timing to open outlet gates (38) of the weighing bucket (33) to transfer the mass to the auxiliary buckets (36); a timer means (2) sequentially measuring, based on the timing, such an additional time length needed to completely transfer the mass remaining in the weighing bucket (33) into the auxiliary bucket (38); a second detecting means (3) detecting a further timing to open outlet gates (39) of the auxiliary buckets (36) to discharge the mass selected in the combination processing; and a setting means (4) setting, based on the further timing, duration of said outlet gate's opened state of the auxiliary bucket, the duration being given by adding the additional time length to such a further time length needed to completely discharge the mass from the auxiliary buckets. The second detecting means (3) and the setting means (4) may be replaced by a deciding means (13) making a decision as to whether or not the mass transferred to the auxiliary bucket (36) is subject to selection, based on a remaining time length measured by the timer means (12) is or is not zero, the remaining time length being given by subtracting a combination-computing time from an ordinary time length necessary for the mass in the weighing bucket (33) to be completely transferred to the auxiliary bucket (38).