To provide a centrifugal defoamer which suppresses mixing of large-sized air bubbles in the course of defoaming and improves the defoaming efficiency even for a high viscous raw liquid.

The centrifugal defoamer possesses a cylindrical box rotor constituted rotatably centering a rotary shaft and separating the raw liquid into a defoamed liquid and a foaming liquid by giving centrifugal force to the raw liquid existing in a defoaming chamber in the rotor, and is provided with a hollow shaft having an outer cylinder and an inner cylinder arranged so that they extend outside of the defoaming chamber and the rotary shaft is located inside, and a regulating plate having the surface extending radially around the inner cylinder. The outer cylinder divides a raw liquid feed opening by an outer peripheral surface and an opening and is provided with a foaming liquid inlet on the peripheral wall positioned nearer at the opening side than the regulating plate. The inner cylinder forms a foaming liquid passage through which the foaming liquid passes by the outer peripheral surface and the inner peripheral surface of the outer cylinder, is provided with a defoamed liquid inlet on a peripheral wall positioned more apart from the opening than the regulating plate, and forms a defoamed liquid passage through which the defoamed liquid passes with the inner peripheral surface.