Gauge invariant gravitation theory. 1: Gravitational field source and spin

It is shown that gauge invariance occurs as the consequence of physical field (fields with certain spin) description by the values, transformed as irreducible representations of homogeneous Lorentz group. Gauge invariant lagrangian of the field of 2 spin was constructed. It was proven that gravitational field represented the superposition of gauge invariant fields of 2 and 0 spins. Occurrence of the zero spin field is directly related with nonpreservation of the (gauge invariant) source of gravitational field.