A method of introducing collective motion into the layered Fermi fluid (LFF) is discussed by concentrating on layer vibrations. By the random phase approximation (RPA), the original dynami· cal degrees of freedom of particles are separated into collective modes (eMs), uncorrelated (harmonic) oscillator modes (UOMs) and two-dimensional (2D) motions of particles within layers, which leads to a subband structure of particle spectrum. Transverse eMs cause the system's instability in case the interaction potential has too high a repulsive core. A primitive estimation of the correlation energy Lls due to eMs is presented in the Hartree-Fock approximation for a simple toy model with a square well potential. ILlsl is shown to be maximized when eMs are sustained by about one half of particles. There exists a density above which the Fermi surface intersects the lowest two bands and the interaction among eMs and particles will become attractive to provide a possible mechanism of superftuidity and/or superconductivity. The purpose of this paper is to develop the quantum theory of layer vibrations of laminated 2D Fermi fluid (LFF). The motivation is the theoretical investigations of dense nuclear matter made during the last sixteen years in the view called the alternating layer spin structure (ALS) model.l)-6) However, the principal idea to be presented below will be equally applied to any analogous fermionic systems. We will come back to this topic in the last section. The physics of dense nuclear matter has been attracting much attention in connection with the discovery of neutron stars as pulsars. Studies of finding out the true ground state in high density regime have been the central part of this field and, so far, been focused on fluid, solid and the ALS phases. Among them the ALS phase proposed by Takatsuka et aU) seems intriguing in providing the lower energy state than the Fermi gas and its physical properties have been studied extensively,2) ranging over the possibilities of existences of protons,3) isobars,4) charged pion condensation,5) superfluidity,6) etc. In the simple ALS model of neutron matter/) particles consisting of neutrons are supposed to form the LFF. Accordingly, the ground state wavefunction is approx imated by the Slater determinant of the single particle wavefunction rp of the follow ing type: