Conventionally, the estimation of the surface magnetic field in pulsars is based on the knowledge of the spin-down causing dipolar
magnetic field, taken at the neutron star radius. We demonstrate that observations of thermal X-ray emission from pulsars implicates, that surface magnetic field at the polar cap is up to two orders of magnitude stronger than the conventional dipolar component. Therefore, surface magnetic field in pulsars must be highly non-dipolar. We present the observed values of black body temperature and bolometric luminosity of X-ray emission, which depend on the surface magnetic field. Thus we can infer the properties of surface magnetic fields in pulsars.