  The origin of a part of the single pulsars with relatively low magnetic
fields B < 1E12 G and with characteristic times Tau < 1E7 yr is established.
Such pulsars occur as a result of the disruption of High Mass X-ray Binary
Systems after a second Supernova explosion. In these binaries mass accretion
onto the surface of X-ray pulsars leads to the decrease of the magnetic field
from its initial value B ~ 1E12-1E13 G down to B < 1E12 G similar to the
processes in Low Mass X-ray Binaries.
