To provide a force feeding method of dewatered sludge and to provide the dewatered sludge for force feeding that can be executed inexpensively, and can secure maintenance properties for comparing favorably with the conventional ones since the need for increasing pump power and piping diameter is eliminated and piping facilities can be configured by using normal piping by improving treatment when force-feeding the dewatered sludge by a force feeding means and the dewatering sludge for force feeding itself.

When the dewatered sludge, where the sludge is dewatered, is forcibly fed by the force-feeding means, lubricant for softening the dewatered sludge is added to the dewatered sludge. Lubricant has a considerable number of calorific values. Additionally, the lubricant has hydrophilic properties that are dissolved in moisture in the dewatered sludge. As one example of the lubricant, hydrophilic glycerin can be listed. The hydrophilic glycerin is added by 5-40% in terms of a weight ratio to the dewatered sludge whose water content is 40-85%.