Abstract: An object of the present invention is to provide a method capable of producing a protein fiber in which shrinkage at the time of first contact with moisture after production is more reliably suppressed and generation of crimp is also suppressed. A method for producing a protein fiber according to the present invention includes: a pre-shrinking step of shrinking a protein fibril in a relaxed state after drawing and before being wound; a winding step of winding the protein fibril subjected to the pre-shrinking step to obtain a wound product; and a post-shrinking step of shrinking the protein fibril subjected to the winding step in a relaxed state.

Abstract: Disclosed is a method for manufacturing a fibroin solution including a step of forming a slurry containing a solvent-containing dissolving liquid and a fibroin-containing protein powder dispersed in the dissolving liquid by continuously introducing the protein powder to a thin film of the dissolving liquid while flowing the thin film; and a step of forming a fibroin solution by dissolving, in the dissolving liquid, the protein powder in the slurry.