Based on the flow calorimetry, a new flow calorimeter for the accurate measurement of isobaric specific heat capacities of gases was constructed. Measurements of the specific heat capacity of difluoromethane were carried out in the temperature range from 303 to 343K at pressures up to 0.5MPa. To confirm the reliability of this experimental apparatus, measurements were performed on carbon dioxide at temperature from 298 to 342K. The heat capacity data obtained agreed with those given in the IUPAC Tables with maximum deviation of 1.53%.