The aim of this study is to elucidate the role of each substituent such as Al, Mn and Co in the H2 absorption of LaNi4.5Al0.5, LaNi4.5Mn0.5, LaNi2.5Co2.5 alloys by the measurements of temperature and pressure dependences of the H2 absorption rate. The pressure dependence of the reaction rate was observed, but the pressure dependence of the reaction rate was independt of the temperature change between 273K and 353K. And the activation energies of reaction rates of all sampls were lower than that of LaNi5. The effect of substitution was clearly observed in the kinetics.