01-01U

It is shown that the partition function for the pseudospin-electron model with direct interaction between pseudospins but without electron transfer and transverse field can be expressed in terms of the partition function for the Ising model in a temperature dependent external field. It is proved that in the regime of constant chemical potential $\mu $, temperature first order phase transitions with jumps of mean values of pseudospins and average electron concentration $n$ exist. In the $n=const$ regime, the separation into phases with different values of these magnitudes takes place. Exact expressions for the phase coexistence curve ($\mu =const$) and the phase separation curves ($n=const$) are obtained.