  We study phase transitions in the Next-to-Minimal Supersymmetric Standard
Model (NMSSM) with the weak scale vacuum expectation values of the singlet
scalar, constrained by Higgs spectrum and vacuum stability. We find four
different types of phase transitions, three of which have two-stage nature. In
particular, one of the two-stage transitions admits strongly first order
electroweak phase transition, even with heavy squarks. We introduce a
tree-level explicit CP violation in the Higgs sector, which does not affect the
neutron electric dipole moment. In contrast to the MSSM with the CP violation
in the squark sector, a strongly first order phase transition is not so
weakened by this CP violation.
