To provide a heat sealing adhesive in which influence of heat seal temperature to heat seal nature adhesive strength is small, and a heat seal nature lid material using the same.

The heat seal nature lid material 12 includes a substrate 16, a design layer 16 prepared on the surface, and a heat seal nature resin layer 18 prepared on the back surface. The heat seal nature resin layer 18 is formed as follows. The heat sealing adhesive in which silica is distributed in a liquid composition in which a carboxylic acid modified propylene (co)polymer is dissolved or dispersed in a solvent is coated on the substrate 16 and is dried.