PROBLEM TO BE SOLVED: To provide a device for removing a hard deposition formed on an irregular shellfish surface.SOLUTION: In order to correspond to the irregularities of a shell surface, there is prepared a circular rotary member 150 made of an elastic endless belt having claws on an outer peripheral surface. Said circular rotary member is rotated to draw an elliptical track so that a claw 170 of the outer circumference of the circular rotary member removes a hard deposit on the shellfish surface while sliding along the irregularity of the shellfish surface.