PRODUCTION METHOD FOR DRY SOLID CONTAINING FINE CELLULOSE FIBERS， DRY SOLID CONTAINING FINE CELLULOSE FIBERS， REDISPERSION OF FINE CELLULOSE FIBERS

[Problem] To provide: a dry solid that contains fine cellulose fibers and has excellent redispersibility in solvents such as water; a simple production method for a dry solid that contains fine cellulose fibers; and a redispersion of fine cellulose fibers that has excellent transparency and viscometric properties. [Solution] According to one embodiment of the present invention， the dry solid that contains fine cellulose fibers contains fine cellulose fibers into which at least 0.5 mmol/g of sulfo-group-derived sulfur has been introduced. The production method for a dry solid that contains fine cellulose fibers includes a step for drying at low pressure and a comparatively low temperature. The redispersion of fine cellulose fibers includes the redispersion of fine cellulose fibers and water and has excellent redispersion characteristics in terms of transparency， viscometric properties， and precipitation characteristics.