The average density ([rho](PCPS)) Of the pauci-chain polystyrene microlatices (PCPS), which contains a few linear polystyrene chains, was investigated by laser light scattering (LLS) including both angular dependence of absolute integrated scattered intensity (static LLS) and of the line-width distribution G(gamma) (dynamic LLS). In static LLS, the weight-average particle mass (M(w)) and the z-average radius of gyration (R(g)) were measured; and simultaneously in dynamic LLS, the hydrodynamic radius distribution was obtained from Laplace inversion of very precisely measured intensity-intensity time correlation function. A combination of both the static and dynamic LLS results leads us to a value of [rho]. For comparison, we also determined [rho] of conventional multichain polystyrene latex (MCPS) by following the same LLS procedure. It was found that [rho](MCPS) = [rho](bulk) = 1.05 g/cm(3), but [rho](PCPS) = 0.92 g/cm(3). This difference in density suggests that the intersegmental distance in MCPS or bulk polystyrene is smaller than that in PCPS, even the chains in PCPS are confined to a smaller volume. This might attribute to the fact, namely the intersegmental approaching inside PCPS is mainly the intrachain crossing which is more difficult in comparison with the interchain crossing inside MCPS or bulk polystyrene.