  Spectra of masses are calculated for the families of doubly heavy baryons in
the framework of nonrelativistic quark model with the QCD potential by
Buchmuller--Tye. We suppose the quark-diquark structure for the wave functions
and take into account the spin-dependent splittings. The physical reasons
causing the existence of quazi-stable excited states in the subsystem of heavy
diquark are considered for the heavy quarks of identical flavors.
