Time perspective(TP)is the unconscious process about past, present, future and predicts individual behavior. Therefore, TP will be able to predict the Happiness Enhancing Activities(HEA) that people perform to increase happiness in everyday life. present have relevance to pleasure, past and future have relevance to meaningful. These results support the relationship between Orientations to Happiness(OTH) and TP. Hence the present study examines the relationship among TP(composed of Past-Positive, Present-Hedonistic, and Future), OTH(composed of pleasure, meaning, and engagement), and HEA. Two samples were collected by dividing 197 of early-adults and 182 of middle-aged adults. The study was measured by questionnaires including the ZTPI, K-OHQ, HAPPI. The data were analyzed by the Multiple mediator models with SPSS Macro. As a result of the significance test for the mediating effect of OTH in the relationship between TP and HEA: significant in both groups. In the early-aged adults, β= .19, 95% Bias-Corrected=[.12, .29]. In late middle-aged adults, β= .23, 95% Bias-Corrected=[.15, .34]. The result of the study may indicate that not only the attitude toward time but also the tendency to pursue happiness is important ways to Happiness Enhancing Activities. Our findings can contribute to understanding how to increase happiness.