  Observed properties of GRBs, WR stars and their CO-cores in the end of
evolution are analyzed. A possible bimodality of the observed GRB energy
distribution ($10^{48}$ erg for GRB9809425; $3\times 10^{51}\div 2\times
10^{54}$ erg for others) is in accord with the bimodal mass distribution of
relativistic objects ($M_{NS}=(1.35\pm 0.15) M_\odot$; $M_{BH}=(4\div 15)
M_\odot$). The peculiarity of SN1998bw can be related to the rotation of the
collapsing CO-core. The expected galactic collapse rate of CO-cores of most
compact WR stars of type WO is $\sim 10^{-5}$ per year, only by one and a half
order of magnitude higher than the GRB rate. The allowance for a gamma-ray
beaming or random outcome of the CO-core collapse due to some instabilities
brings this rate in accordance GRB rate. We argue that WR stars (most probably,
of type WO) can be considered as progenitors of cosmic gamma-ray bursts. Two
types of GRBs are predicted in correspondence with the bimodal mass
distribution of the relativistic objects. Three types of optical afterglows
should appear depending on which CO-core is collapsing: of a single WR star, of
a WR star in a WR+O or a hypothetic WR+(A-M) binary system. We briefly discuss
a model of GRB as a transient phenomenon occurring at early stages of galactic
evolution ($z>1$), when very massive ($M>100 M_\odot$) low-metallicity stars
could form. WR-galaxies can be most probable candidates for GRB host galaxies.
