Static magnetization in solid 3He has been measured from 10 mK down to 0.3 mK for various molar volumes V (from 24, 14, to 19.26 cm3/mole). The results for bcc 3HHe show that both the ordering temperature TN and inverse of the maximum magnetization at TN vary in proportion to V16.5±1, that the magnetization in the ordered state is almost constant, and that the magnetization reduced by its maximum value is represented by a universal function of the reduced temperature T/TN. The magnetization in hcp 3He shows that its Weiss constant is very small, possibly less than 30 μK.