To provide a warp-sizing apparatus in which permeation of a sizing liquid into warp is sufficiently carried out by always clean sizing liquid.

The warp-sizing apparatus has at least one sizing liquid tank and carries out sizing by immersing a warp sheet in which a plurality of warps are arranged in sheet-like state into the sizing liquid in the sizing liquid tank. The warp-sizing apparatus comprises a first liquid tank in which the warp sheet is immersed into a liquid at first in a moving direction of the warp sheet, an auxiliary tank for recovering the liquid which flows out from the first liquid tank and a feed means for feeding the liquid recovered in the auxiliary tank to the first liquid tank again, and further, oil separation apparatus for separating oil mixed into the liquid in a circulation passage including the first liquid tank, the auxiliary tank and the feed means from the liquid and recovering the oil is additionally installed in the warp-sizing apparatus.