This study is to examine the effect of mutualistic benevolence, altruistic benevolence, and communication on affective commitment, calculative commitment, and switching intentions and investigate how two commitment dimensions play mediating roles between two benevolence constructs and communication, and switching intentions. For these purposes the author developed a structural model which consists of several constructs. In this model, benevolence factor that consists of mutualistic benevolence and altruistic benevolence, and communication were proposed to affect two commitment constructs and result in, increase switching intentions. Thus, two commitment constructs(e.g., affective and calculative commitment) were proposed as core mediating variables between mutualistic benevolence, altruistic benevolence, and communication, and switching intentions. The data were collected from 210 automobile parts buyers and were analyzed using frequency, reliability, and confirmatory factor analysis and SEM (structural equation model) with SPSS/WIN 20.0 and AMOS 20.0. The data were analyzed with structural equation modeling with AMOS 20.0 and SPSS Win/PC 20.0. The result of the overall model analysis appeared as follows: ${\chi}2=224.885$, d.f=123(${\chi}2/df=1.828$), p=0.000, GFI=.898, AGFI=.859, IFI=.967, NFI=.930, TLI=.958, RMSEA=.063, CFI=.966. Since the result of the overall model analysis demonstrated a good fit, we could further analyze our data. The findings can be summarized as follows: According to structural equation modeling analysis, firstly, mutualistic benevolence has direct effects on calculate commitment and affective commitment. Secondly, altruistic benevolence has a positively direct effect on calculate commitment. Thirdly, communication has a statistically direct effect on affective commitment. Fourthly, calculative commitment has direct effects on affective commitment and switching intentions. Lastly, affective commitment has a direct effect on switching intentions.