This invention relates to the isolation of thermophilic phytase-producing microorganisms, method for producing phytase using such microorganisms, phytase obtained therefrom, and usage of the phytase to hydrolyze phytic acid or phytate. In particular, this invention relates to phytase-producing microorganisms, which belong to Streptomyces sp., Pseudonocardia sp. or Microbispora sp., and which produce phytase available for recovery in an efficient and practical manner.