PURPOSE: To enhance the efficiency and omit both of transferring and dipping operations of earth and sand.

CONSTITUTION: A memory circuit, storing the three-dimensional form data of earth and sand 2 at prior to excavation, is installed in a power shovel 1 whose earth-sand digging bucket 15 is rockably pivoted to a tip 142 of a second arm 14 for transferring the earth and sand 2. On the basis of the three- dimensional form data of the earth and sand 2 stored in this memory circuit, a main controller determines such a digging spot as capable of digging the earth and sand 2 so efficiently by the bucket 15.