In this study, in order to clarify a interaction between thermodynamic effect, which suppresses cavitation, and scale effect, which promotes cavitation, tunnel experiment was done with NACA16012 single hydrofoil in hot water. Appearance of the effects was estimated by occurrence condition of cavitation for angle of attack vs cavitation number. And the cause of thermodynamic effect is estimated by measuring the temperature depression inside the cavity. Mainstream temperature was 30 °C and 70 °C. By increasing mainstream temperature under constant Reynolds number condition, scale effect was took away to some extent and thermodynamic effect was picked out. From the result, occurrence resin of cavitation was suppressed in 70 °C hot water, where it is empirically known that thermodynamic effect does not appear in such a low temperature. The result indicates that thermodynamic effect and scale effect, which are conflicting effects, cancelled each other in water at 70 °C. Additionally, it was shown that occurrence of cavitation was drastically suppressed in a condition under specific range of angle of attack.