PURPOSE: To provide the titled ultra-thin stencil paper excellent in heat resistance, humidity resistance and shape stability and low in a warp and weft strength ratio, obtained by forming a sysnthetic fiber, in which a specific amount or more of a synthetic fiber having a monofilament diameter of a specific value or less is compounded, into paper with a specific thickness by a wet paper making process.

CONSTITUTION: A synthetic fiber with a monofilament diameter of 8μm or less, which is obtained by spinning and stretching a polymer pref. having a dry heat melting temp. of 200°C or more and a moisture absorbing ratio of 5% or less, for example, polyamide of PVC, is compounded in a synthetic fiber in an amount of 30% or more. This fiber is formed into paper with a thickness of 20W40μm by a wet papermaking process to obtain the objective stencil paper pref. having the ratio of warp direction tensile strength to weft direction tensile strength of 2:1W1:2 and constitutional fiber density of 0.200W0.450g/cm2 and reduced in thickness speckle.