Abstract: An explosive slurry composition having excellent suspension stability, good thixotropic characteristics, high detonation power and good temperature characteristics comprises as ingredients a water-swollen gel of a complex composed of sodium montmorillonite and a water-soluble organic compound having a polar group, and an oxygen supplier such as ammonium nitrate and/or a sensitizer such as aluminum powder and/or a fuel such as saccharide, fuel oil and the like. This explosive slurry composition is used for blasting hard rocks and the like in situ connected with a booster or cap.