PROBLEM TO BE SOLVED: To improve shellfish drilling work.SOLUTION: A shellfish drilling method is configured as follows: shellfishes are vertically put one by one on each of two rotationally moving shellfish carriers and are vertically conveyed by respective shellfish carriers； drilling parts of the shellfishes are positioned in a predetermined direction during conveyance by respective shellfish carriers； those shellfishes are held in a holder in a positioning state to continue conveyance； respective electric drills are moved with a synchronized manner in the same direction as the conveying direction of the shellfishes while being held and conveyed, at the same speed as the shellfish conveyance speed； respective electric drills are advanced during the synchronous movement, and the rotating drill bits continue to drill holes into the drilling parts of the shellfishes while being held and conveyed by respective shellfish carriers； the respective drill bits are retracted and extracted from the shellfishes after drilling completion, and the respective electric drills are returned to the initial position and moved； those electric drills are synchronously moved in the same direction and in the same speed as the shellfish being held and conveyed next in a positioned state, and those drill bits continue to drill holes in the drilling parts of the shellfishes； the drill bits are extracted from the shellfishes after drilling completion, and the electric drills are returned and moved to drill the holes in the shellfishes being conveyed sequentially； and this is repeated to drill the holes in the shellfishes being conveyed sequentially.SELECTED DRAWING: Figure 12
