Saesongi (Pleurotus eryngii) was cultivated in both potato dextrose agar (PDA) and sawdust media supplemented with Ca salts. The addition of Ca phosphate and Ca carbonate to sawdust media did not affect the growth, whereas Ca sulfate addition suppressed the mycelial growth appreciably. The efficiencies of Ca accumulation in the fruiting were studied based on mycelial growth experiments on Ca-supplemented sawdust media. Supplementation with 0.1 to 5% Ca phosphate increased the Ca content in the fruiting body by 4.5-6.5 fold, to a level of $314.6{pm}22.7$ to $449.7{pm}29.3$.