  We review our recent works about ``pasta'' structures following the
first-order phase transition in dense matter, which correspond to the
structured mixed phases with geometrical symmetries. Three kinds of phase
transitions at different density ranges are examined as the stages of pasta
structures: liquid-gas phase transition at subnuclear density, kaon
condensation and hadron-quark phase transition at high density. Charge density
as well as particle density is non-uniform there. A consistent treatment of the
Coulomb potential and the particle densities is presented and a peculiar role
of the Coulomb potential is elucidated: the physical picture of the Maxwell
construction will be effectively recovered. It largely influences the density
regime of pasta structures by the charge screening effect.
