LNG (Liquefied Natural Gas) vaporizer is widely used all over the world to vaporize LNG by using seawater, etc. as a heating source. Intermediated Fluid type LNG Vaporizer (IFV) is using intermediated fluid between LNG and heating source. Propane has been used as an intermediated fluid conventionally, but new refrigerants except for propane are required because usage environment was diversified recently. In this study, refrigerants substitute for propane applicable to IFV were selected as R32 and R410A. On the basis of some experimental formula, prediction of boiling and condensation heat exchange quantity in tube bundles was also carried out and it enabled to predict actual IFV vaporization quantity with plus or minus 2 percent accuracy. The prediction demonstrated that those selected refrigerants can increase the vaporization rate with IFV from the base line of propane.