High pressure neutron and magnetization experiments up to P equals 21 kbar and H equals 50 kOe, in the temperature range 3-32 K, have established pressure sensitivity of several magnetic phases of CeSb. Type I phase observed in critical scattering above T//N is found to be stabilized at about 2. 5 kbar. Two completely new phases are observed between type I and type IA phases at P greater than equivalent to 10 kbar.