PURPOSE: To obtain a cellulose-system yarn film where the hole form and the film thickness are uniform, by using dimethyl sulfoxide solution including aldehydes of cellulose as the element for film formation and by spinning yarn with non-solidified liquid of this solution as core component under dry and wet spinning.

CONSTITUTION: High purity pulp such as linter pulp is dissolved in dimethyl sulfoxide including aldehydes, and solution where cellulose is modified to methyloled cellulose is used as the material for film formation. Hexane, heptane, decane, dodecane, decalin, liquid paraffin, etc., or aliphatic hydrocarbon of a comparatively long chain having a substituent such as halogen and ester radical, for example, non- solidified liquid of fromo-dodecane or myristic acid ester is used as core component. A composite spinning capsule arranged coaxially is used to spin yarn with cellulose solution and non-solidified solution as sheath component and core component respectively under dry and wet spinning, and core component is removed after sheath component is solidified, thereby obtaining a hollow yarn film.