Microbial hydrogel was prepared with poly(${gamma}$-glutamic acid) produced from Bacillus subtilis BS62 using crosslinking reagent, ethylene glycol diglycidyl ether (EGDE), and its physico-chemical characteristics were examined. Hydrogel which prepared from 10 grams of 10% PGA solution with $600;{mu}l$ of EGDE at $50^{circ}C$ for 17 h swelled 4,320 times its dry weight, and time to reach swelling equilibrium in deionized water at 4 to $45^{circ}C$ range was about 20 h. Swollen hydrogel shrunk in ionic solutions, and rate of shrinkage was higher in calcium chloride solution than sodium chloride solution. Swelling rate of hydrogel increased 1.3-fold of initial swelling rate for 30 min at $80^{circ}C$.