This paper incorporates the interdependent relationship of firms and t
he increasing consumer density into a framework of spatial equilibrium
analysis, and studies the location of firms and the price system on a
plane market. As consumer density increases, symmetric equilibrium is
established initially for the first- and the second-round entry of fi
rms, but this equilibrium becomes unequal later for the third and the
fourth rounds. This fact means that in spatial equilibrium even if all
firms sell identical goods on a plane market, mill prices and market
area sizes will differ.