By dividing public conflict phases into pre-politicization and post-politicization, the study explored the socio-economic cost factors of public conflicts, and estimated the soci-economic cost of the Miryang power line tower case. The direct cost is estimated by multiplying the number of conflict days, the number of participants, and the market wage rate, then adding the indirect cost of additional socio-economic costs. The study estimated that the Miryang power line tower case incurred approximately 430 million KRW during the pre-politicization phase, and approximately 9.6 billion KRW during the post-politicization phase. Therefore, the estimates shows a 22.3 times higher cost incurring during the post-politicization phase than the pre-politicization phase. In conclusion, the governments need to manage public conflicts before they escalate into political fares in order to minimize the soci-economic costs.