This paper analyzes how the shopping behavior of consumers influences upon retail facility location within the context of multi-purpose shopping. We make a model of optimal frequencies of single- and multi-purpose trips and derive the degree of multi-purpose shopping from it. It is shown that consumers' spatial behavior is a function of their locations relative to retail facilities. This analysis is then utilized as an input to the profit-maximizing equation of retailers. The model is illustrated through the use of numerical analysis.