A grinding apparatus includes a holding unit including a holding table having a holder for holding a workpiece and a grinding water suction part for drawing in grinding water outside of the holder, a rotational shaft having an end fixed centrally to a bottom surface of the holding table, a tubular rotary joint surrounding the rotational shaft, and a motor rotating the rotational shaft about its own axis. The rotational shaft has a first suction channel held in fluid communication with the holder of the holding table and a second suction channel held in fluid communication with the grinding water suction part. The rotary joint has a communication channel by which the first suction channel and the second suction channel are held in fluid communication with at least a suction source.