Critical Compressibility Factor of TwoDimensional Lattice Gas  Kagome and Diced Lattices The critical compressibility factor Zc at the gasliquid critical point is defined by Zc=pcVc/Nk_{B}Tc (pc: critical pressure, Vc: critical volume, Tc: critical temperature, k_{B}: Boltzmann's constant, N: number of molecules). The Zc of the lattice gas on the Kagome or diced lattice is discussed. First, on the basis of exact solution for the partition function Z of the Ising model without magnetic field on these lattices, the Zc is calculated exactly. The results are Zc=0.08330842... (Kagome lattice) and Zc=0.14284554... (diced lattice). Secondly, high temperature expansion for Zc is studied and the expansion is carried out up to w^{13} for the Kagome lattice and up to w^{12} for the diced lattice. Extrapolation procedures for obtaining Zc are discussed. A similarity between the diced and Penrose lattices and the one between the Kagome and dual Penrose lattices are pointed out. 
