The purpose of this paper is to investigate the characteristics of direcct-contact condensation heat transfer. The jet of Freon vapor (R11 and R113) was injected against a uniform water stream in the vertical tube of inside diameter D=30mm. The temperature distribution in the vertical direction was measured for water flow rate Q_w=5∼20×^-6m³/s, Freon liquid flow rate Q_f=0∼2.17×10^-6m³/s and temperature difference ΔT=T_s-T_w=5∼35K. The results of experiment on the heat-transfer characteristics clarified the relation between the height of effective heat-exchange region, H and the ratio of heat-exchange quantity to its critical value, φ/φ_c.