This paper aims to identify the causal structures underlying trip chaining behavior. The paper also empirically examines changes between 1970 and 1980 in the causal relationships among factors affecting on the chaining formation. A multiple-stop trip chain is here defined as a chain of trips that contains at least more than two stops for non-work activities in addition to one work activity. These data sets between two points over time are used for a path analysis. The path analysis will allow us to quantitatively explore the decision mechanisms through an estimation of path coefficients between factors. The analysis has indicated that causal structures varied more in 1980 than in 1970 and also that the causal-effect relationship between the travel mode and time durations for non-work activities is strongly determined by both the time-expenditure and the added travel distance.