The Henry's law constants and partial molar volumes at infinite dilution for helium in CF₄ and CClF₃ have been extracted from the experimental phase equilibrium data^1） using the Krichevsky-Kasarnovsky equation³⁾ and also theoretically predicted. It has been found that the Henry's law constants for the systems considered in this work are larger than those for any other helium binary systems investigated so far at a given reduced temperature. The hard sphere model of fluids as presented by Snider and Herrington²⁾ has been used to predict the Henry's law constants and the partial molar volumes at infinite dilution. The predicted values agreed with the experimental values within at most 55 % of the experimental values.