To open the most efficient place in a case of opening shell of scallop and to take out adductor without damaging fibers of the adductor in a case of taking out the adductor from a shell.

A scallop X is fixed by a fixing means and the shell is opened by obliquely cutting from about center of a hinge side of the shell to a prisma side at a prescribed angle. The prescribed angle is about 30-60°, preferably 45° from the hinge. In the taking out the adductor, the adductor is protected by sucking DOBU (viscus excepting adductor, HIMO and URO).HIMO (mantle).URO(mid-gut gland) while temporarily fixed by a pushing board corresponding to a size of the adductor, and the adductor is taken out.