To provide a vertical centrifugal separator which certainly washes the interior of a separation chamber and can efficiently reutilize a separated solid.

The vertical centrifugal separator is equipped with an outer cylinder 1 rotatable around an axial line extending in an almost vertical direction, an inner cylinder 5 rotatable around the axial line in the outer cylinder, the screw blade 3 attached to the outer peripheral surface of the inner cylinder 5 and arranged so as to form a slight gap with respect to the inner wall surface of the outer cylinder 1, the supply pipe 39 provided in the inner cylinder 5 and supplying a slurry to be treated to the separation chamber S between the outer cylinder 1 and the inner cylinder 5, a planetary gear mechanism 3 connected to the lower ends of the outer and inner cylinders 1 and 5 to transmit the rotation of the outer cylinder 1 to the inner cylinder 5 to rotate the outer and inner cylinders 1 and 5 in the same direction so as to generate a predetermined difference in the number of rotations, a motor 35 for rotationally driving the inner cylinder 5 and an introducing pipe 59 piercing the planetary gear mechanism 43 to extend into the inner cylinder 5 and capable of ejecting a washing liquid or air to the solid separated in the separation chamber S from the inner wall of the inner cylinder 5.