Objectives: This study looked at the actor-partner interdependence effects between middle-aged couples' attachment and marital intimacy using surveys collected from 208 middle-aged couples. Methods: Total 208 middle-aged couples participated in the study through online surveys used for data collection. Data were analyzed applying SPSS 25.0 and AMOS 25.0. Results: First, when both partners were anxious attachment type, the husband's actor and dependence effects were significant, but the wife’s actor-dependence effect on marital intimacy was not significant. Second, when both couples were avoidance attachment type the actor-dependence effects on marital intimacy were significant. Third, when the husband was avoidance attachment type and the wife was anxious attachment type, the husband’s actor effect was significant but dependence effect was not significant. Fourth, when the husband was avoidance attachment type and the wife was anxious attachment type, the husband’s actor-dependence effect on marital intimacy was significant, but the wife’s actor-dependence effect on marital intimacy was not significant. Finally, if the husband was avoidance attachment type and the wife was anxiety attachment type, the wife’s anxiety attachment did not significantly affect the husband’s marital intimacy nor did it affect the wife’s. Conclusions: The results of this study present the direction and basis for intervention to promote marital intimacy in marital counseling.