Abstract: A drilling bucket apparatus for expanding a bore-hole bottom for a cast-in-place pile. Drill bits are pivotally suspended from the upper portion of a drill pipe, which is a main frame of the apparatus, and are expanded and retracted radially by means of hydraulic cylinders. A bucket is attached to the lower end of the drill pipe and scrapers are installed on the side of the bucket. The scrapers are arranged to open and close sideward, following the movement of the drill bits. During drilling work, the apparatus is suspended from a kelly bar of a drilling machine. When the apparatus is rotated and the drill bits are expanded, the whole expanded shape of a bore-hole bottom is drilled simultaneously and cuttings are scraped into the bucket by means of the drill bits and the scrapers. Further, a bottom lid of the bucket can be released by operating a hydraulically-actuated opening laver, whereby, cuttings are discharged automatically.