Korea is about to take part in the MAI (Multilateral Agreement on Investment) and sign the Korea-US investment agreement and so on. One major way to testify the possible trade dissensions we might face under these agreements is to observe the dissension cases under the NAFTA investment agreement which is similar to these agreements. The problems which found in NAFTA dissension cases, such as the discordant standing points among sections, the relationship between the central government and local governments, the coherence of the policies and the unreasonable domestic regulations are also our problems. The dissensions causing by the oversea investors might blemish the image of the country which attracts investments. The most ideal way is to prevent the dissensions. If it happened, it should be solved in a friendly way. This thesis discussed the grievance machinery or trouble shooter which was recently added into the investment promotion act and the effective operation of the foreign investment committee.