In this study, we analyzed whether the downward profit adjustment of the subcontractor's arising from the relationship between customer and subcontractor appears to be differentiated by the effects of the trickle-down effect and the mutual growth efforts of the clients and the government. The results of this study show that the operating profit margin and the net profit margin of the subcontractor that have a high degree of trickle-down effect are superior to those of the subcontractor that have low trickle-down effects and they don’t do downward earnings management to avoid unfavorable contracts. In addition, for the subcontractor that trade with companies with customer that are willing to encourage mutual growth is no tendency to downgrade profits. This result implies that trust relationship and win - win relationship with customer - subcontractor mitigate subcontractor's opportunistic accounting choice. This study empirically analyzed whether the management policy or government policy for trickle-down effect and mutual growth worked effectively and suggested that the establishment of the trust relationship between can contribute to enhance the transparency of accounting.