  From vector measurements of the photospheric magnetic field with the SDO/HMI
instrument, we studied the field variations within the 2011 June 7 eruptive
event related to the filament eruption (FE), flare, and coronal mass ejection
(CME). We analyzed the variations in modulus (B), in radial (Br) and
transversal (Bt) magnetic induction components, as well as in the field line
inclination angle ({\alpha}) to the radial direction from the Sun center were.
The conclusion is that the most probable cause for the FE onset being the
trigger related to the flares and CME, as well as for Stage 1 of the filament
dramatic acceleration, is {\guillemotleft}magnetic flux
cancellation{\guillemotright} in several sites inside and around the filament
channel. We assumed that the flare and the stage of the filament fastest
acceleration are related to a spot emergence near the south-eastern filament
footpoint, in which the field polarity and value satisfy a possibility of this
field magnetic reconnection with the field surrounding the filament. We studied
in detail the time variations in the field line inclination angles within
different sites of the eruptive event. During the filament slow emergence, a
decrease in the field line inclination angles was revealed to occur in its
channel neighboring, whereas the field line inclination angles dramatically
grew in the neutral line neighboring within the flare region after the flare
onset. The flare ribbons at all the stages of their existence are shown to be
located under the photosphere sites with the field modulus local maxima and
with minima of the field line inclination angles. We show that, near the
photospheric magnetic field polarity inversion line (PIL), the azimuth
decreases after the flare onset, which means a decrease in the angle \b{eta}
between PIL and the magnetic induction vector projection onto the sky plane.
