Observed properties of filaments which dominate in large-scale structure of the Universe are considered. A part from these properties isn't described within the standard ΛCDM cosmological model. The "toy" model of formation of primary filaments owing to the primary scalar and vector gravitational perturbations in the uniform and isotropic cosmological model which is filled with matter with negligible pressure, without use of a hypothesis of tidal interaction of dark matter halos is offered.