To solve problems that the finish of a work is dispersant according to the skill of a worker in a manual deburring work, the workability is poor, it takes time to complete the work, some works are left non-deburred, and a conventional deburring machine is large in size, requires a large space for installation, and is expensive and difficult for introduction.

The works held by a chuck are automatically lowered into a grinding tank containing abrasive grains and the liquid, and rotated and reciprocally raised/lowered in the grinding tank for deburring operation. The raising/elevating, and rotation of the works are automatically controlled by a program based on the data experimentally obtained in advance. An upper side of the grinding tank is covered by a lid during the deburring operation to prevent the liquid from being spilled outside. The grinding tank is of a two- tank structure comprising an outer tank and a removable inner tank inside thereof. The grinding solution in the grinding tank is circulated.