In this study, the effect of the mineral matter of Goynuk oil shale on the conversion of organic carbon in kerogen into volatile hydrocarbons, polycyclic aromatic hydrocarbons (asphaltenes, preasphaltenes), and carbon in the solid residue was investigated. Kerogen was isolated by successive HCl, HNO3, and HF treatments. A series of temperature-programmed pyrolysis operations was performed with raw Goynuk oil shale and each product of every demineralization process. The results show that removal of the material soluble in HCl and HNO3 slightly affected the conversion of organic materials in the pyrolysis reactions. In contrast, removal of the material soluble in HF increased the conversion in pyrolysis reactions. This behavior is explained by the inhibitive effect of the silicate minerals. The leaching of mineral matter with HCl, HNO3, and HF caused no remarkable change in the composition of volatile hydrocarbons.