In recent years, ocean renewable energy has been increasingly in the spotlight due to global warming and energy issues etc. Research on ocean renewable energy devices is being carried out by many researchers, companies and countries. Additionally, many sea tests are being carried out by countries with real sea test sites. Ocean renewable energy devices still need to research about a power generation method, an energy conversion efficiency and costs etc. In this paper, Authors focus on the oscillating water column type wave energy converter (called below OWC-WEC). It is considered that the OWC-WEC is useful because a movable part which becomes a cause of trouble is few and can also be used as a breakwater device. In this study, the MPS (Moving Particle Semi-implicit) method is applied to the performance analysis of the OWC-WEC. It is because the performance analysis by various parameters and the reduction of an experimental cost is needed. In this paper, these following items are shown; 1) the development of analysis program code which can simulate the multiphase flow by three phases of gas, liquid and solid, 2) the development of air duct model, 3) verification of the usefulness of the improved MPS program code and 4) verification of the applicability to the performance analysis of the OWC-WEC. This program code was applied to the simulation of the fixed type OWC-WEC. Following this, the reproducibility of the primary conversion efficiency of the fixed type OWC-WEC by this program code was verified and discussed. Finally, the usefulness and applicability of this program code were discussed and recommendations for future work were made.