engine in the pressure resistant seal 30 the inner flange of the metal core 31 is into to the lip body 33 to strengthen the waist of the lip body 33 so that the inner lip 34 is strongly urged to the side 23a of the inner step 23 therefore while the pressures in the inside and the outside of the bearing are sutstantially similar the inner lip 34 may disadvantageously be worn out and the starting torque may become larger fig3 shows another preferred embodiment of a pressure resistant seal to improve the above points like elements corresponding to those in fig2 are not described in detail but the different elements only are described in detail in a pressure resistant seal 30a a metal core 31a is not inserted into a lip body 33a and not positioned within the annular concavity 25 so that the waist of the lip body 33 is somewhat weakened as compared with the case of fig2 further an inner lip 34a and an outer lip 35a being positioned in front of the annular concavity 25 formed on the shoulder of the inner race 21 are formed as described below the inner lip 34a is somewhat inclined so as to expand to the outer side radially when the pressure in the outside of the bearing can compete with that in the inside of the bearing the inner lip 34a can be slightly in contact with the side 23a of the inner step 23 when the pressures in the outside and the inside of.