From the recent studies, it has been found that the differential cross sections of the elastic Ndscattering at the energy below 150 MeV can be well reproduced by incorporating the 3NF in the Faddeev calculation based on modem nucleon-nucleon (NN) interactions. On the other hand, the differential cross sections of nd and pd at 250 MeV show large discrepancies between the data and the Faddeev calculations with 3NF. It indicates the presence of the missing features of the three nucleon system at this energy region. For the next step of the 3NF study, we measured the vector analyzing power Ay and the differential cross sections for the 211(p, pp)n breakup reaction at 250 MeV. The experiment was carried out by detecting two protons in the final state with using the double-armed spectrometer Grand Raiden (GR) and Large Acceptance Spectrometer (LAS) at Research Center for Nuclear Physics (RCNP). These data provide important information on the 3NF effects and make a discrimination between 3NF models.