To provide a dehydration accelerator of lime sludge which has low foaming property and stably reduces the moisture content of lime sludge cake even if process conditions vary in a causticizing process of kraft pulp manufacturing, and to provide a dehydration acceleration method of lime sludge using the same.

There are provided the dehydration accelerator of lime sludge containing single specific polyethylene oxide amino ether, or a combination of the specific polyethylene oxide amino ether with specific polyoxyethylene polyoxypropylene alkyl ether as an effective component, and the dehydration acceleration method of lime sludge using the same.