  Relativistically covariant form of equation of motion for real particle
(neutral in charge) under the action of electromagnetic radiation is derived.
Various formulations of the equation of motion in the proper frame of reference
of the particle are used.
  Main attention is devoted to the reformulation of the equation of motion in
the general frame of reference, e. g., in the frame of reference of the source
of electromagnetic radiation. This is the crucial form of equation of motion in
applying it to motion of particles (cosmic dust, asteroids, ...) in the
Universe if electromagnetic radiation acts on the particles.
  General relativistic equation of motion is presented.
