The value of time is an important factor in cost benefit analysis for transportation investment. This value has been practically determined by wage rate or mode choice analysis for the present. However, any approaches have not considered the change in value of time depending on the economic environment. The value of time is an endogenous variable in optimizing behavior so that it depends on the economic environment. This paper theoretically examines how the value of time changes. The consequence of the examination shows that the value of time changes corresponding to commodity prices, travel fee, travel time as well as the wage, the available time, and the labor time. Moreover, this paper discusses the sign of the changes in the value of time under some hypotheses.