To obtain pentafluoroethane of high purity through easy operations with excellent separation effect by bringing a specific fluorinated hydrocarbon into contact with pentafluoroethane containing chloropentafluoroethane.

A fluorinated hydrocarbon of (B) the formula: CnHaF2n+2-a or the formula: CmHbF2n-b (n is an integer of 5-12; a is an inter of 0≤a≤n+2; b is an integer of 0≤b≤n+1) is brought into contact with (A) pentafluoroethane (abbreviated to C2HF5) containing chloropentafluoroethane (C2F5Cl) to remove C2F5Cl by allowing the component B to absorb the chloride. The amount of the component B is preferably 1-1,000 pts.wt. per 1 pt.wt. of the component A. The component A preferably contains 0.01-40 pts.wt. of C2F5Cl per 100 pts.wt. of CHF5. The component B is preferably C6F14, C6HF13, or C6H2F13.