Abstract: A centrifugation method for separating a high specific gravity substance and a low specific gravity substance from a mixture thereof, which prevents the contamination of the high specific gravity substance in collecting the low specific gravity substance after a separation operation, is provided. The centrifugation method includes centrifuging a mixture comprising a high specific gravity substance, a low specific gravity substance, and at least one of a thermoreversible gel and a dissolved gelling agent capable of forming a thermoreversible gel, in which the thermoreversible gel or the dissolved gelling agent forms a gel layer which separates the low specific gravity substance and the high specific gravity substance. The centrifugation is preferably carried out at a temperature equal to or lower than the gelation temperature of the gelling agent.