The present invention relates to a deacetylation hydrolase of a hyaluronic acid, a hyaluronic acid deacetylated by same and a derivative thereof.The deacetylated Hyaluronic, acid and the derivative thereof of the present invention have the following characteristic: a delayed initial decomposition rate on a living body minimized decrease of molecular weight and viscosity accelerated gelation due to a lower gelation temperature than the gelation temperature for a non-deacetylated hyaluronic acid and an HMSC survival rate that is hardly affected by increased concentration of the deacetylated hyaluronic acid and the derivative thereof in a culture medium. As a result, the deacetylated hyaluronic acid and the derivative thereof of the present invention can be useful as a bioingredient such a delivery system for a cell, gene, drug, and the like, or a support for tissue engineering, etc.
