In a refrigerator employing a combustible refrigerant, a plurality of glass-tube heaters (19a,19b) for defrosting is disposed close to an evaporator (10) of a combustible-refrigerant-sealed refrigeration cycle. By controlling the application of an electric current or voltage to the glass-tube heater (19a,19b), the surface temperature of the heater can be kept below the ignition temperature of the combustible refrigerant. Furthermore, following structures are effective in decreasing the surface temperature of the heater (19) - i) making contact the glass-tube heater (115) to fins (108) of the evaporator, ii) forming the glass-tube heater (139) into a tube-in-tube structure and disposing a sealing member (142) at an end of the glass tube (140,141). Such structured refrigerator prevents the combustible refrigerant from catching fire even if defrosting is performed in an environment where leakage of the refrigerant occurs, and improves poor refrigeration due to residual frost.