In a one-part (one-pack) moisture-curing urethane adhesive comprising a urethane prepolymer having isocyanate groups (NCO) at the terminus, said urethane prepolymer being a reaction product of a polyol and an excess amount of a polyisocyanate, the improvement which comprises adding 0.01 to 5% by weight of a gelling agent based on the whole amount of the adhesive, and optionally adding a thermoplastic urethane multi-block copolymer resin and a thixotropic agent selected from the group consisting of a hydrophilic colloidal silica and a polysiloxane-polyoxyalkylene copolymer. The adhesive of the present invention can obviate float or slippage of glass in the adhesive application of window glass of automobiles.