To provide a moisture curable composition which is a compound mainly composed of a silane-terminal ended modified polymer excellent in workability because of a low viscosity in a high shear velocity, and at the same time, capable of preventing sag of a ceramic tile when attaching a heavy load such as a ceramic tile carried out on an approximately vertical surface of a construction structure since workability is sufficiently high because of a high viscosity in a low shear velocity.SOLUTION: The moisture-curable composition of the present invention is mainly composed of a polymer (A) having a hydrophobic part and a hydrophilic part where a diluent (B) having a predetermined viscosity range, a hydrophobic inorganic particle (C), and a thixotropy agent (D) having a hydrophobic part and a hydrophilic part are blended to exert performance for suppressing a viscosity at a high shear velocity under a definite value, and at the same time increasing a viscosity at a low shear velocity.SELECTED DRAWING: None