Gaseous cavitation, which is the phenomenon of bubbles in dissolved air, influences the fluid lubrication of bearings. Particle methods such as the MPS method [1] and SPH [2, 3] have advantages in handling free surfaces, moving boundaries, and multiphase flows. This paper presents a novel gaseous cavitation model based on the MPS method and Henry's law, which describes gas dissolution and deposition. The MPS method was applied to an incompressible flow in the liquid phase. The gas phase was assumed to be isothermal and was expressed by the equation of state. The SPP model [4] was used for gas-liquid interactions. Ghost particles were used to calculate the volume of the gas phase in the same manner as in the liquid-ring vacuum pump simulation using the MPS method [5]. The proposed method was applied to a hydrostatic problem, and the amounts of gas dissolved in the liquid phase were varied. The resulting pressure agreed with the semi-analytical solution. The mass was shown to be perfectly conserved. REFERENCES [1] S. Koshizuka and Y. Oka, “Moving-Particle Semi-Implicit Method for Fragmentation of Incompressible Fluid”. Nuclear Science and Engineering, 123-3, 421-434 (1996). [2] R.A. Gingold and J.J. Monaghan, “Smoothed particle hydrodynamics: theory and application to non-spherical stars”, Mon. Not. R. Astron. Soc, 181-3, 375-389 (1977). [3] L. B. Lucy, “A numerical approach to the testing of the fission hypothesis”, Astron. J, 82, 1013-1024 (1977). [4] N. Tsuruta, A. Khayyer, and H. Gotoh, “Space potential particles to enhance the stability of projection-based particle methods”, Int. J. Comput. Fluid Dyn, 29-1, 100-119 (2015). [5] K. Shibata, et al. “Numerical simulation of liquid ring pump by a particle method”, CMD2022 6-09, (2022) ACKNOWLEDGEMENT This work was supported by the Japan Society for the Promotion of Science (Grants-in-Aid for Scientific Research, Grant Nos. 21K03847 and 23K04248)