an apparatus for cylindrically grinding workpieces includes a first holding tool for positioning pre - grinding workpieces and a second holding tool for positioning partially ground workpieces . the first holding tool defines a first groove for containing the pre - grinding workpieces to be partially ground and the second bonding defines a second groove for containing the partially ground workpieces . at least one first resisting member and at least one first back plate detachably connect with the at least one first holding member , and thus making up the first holing tool . at least one second resisting member and a at least one second back plate detachably connect at least one second holding member , and thus making up the second holding tool . the present invention also provides a process for cylindrically grinding workpieces .