To provide an infill repair material that is lightweight and easy to apply, is excellent in workability because curing is performed at proper speed, and is also excellent in toughness, water resistance, warm water resistance, and weatherability.

The lightweight infill repair material includes a component (A), a component (B), and a component (C) and has specific gravity of less than 1 as follows: (A) an anionic group-containing alkoxysilyl group-terminated polymer obtained by reaction of a compound (A1) containing no anionic group and a plurality of isocyanate reactive groups, a compound (A2) containing an anionic group and a plurality of isocyanate reactive groups, a polyisocyanate compound (A3), and isocyanate reactive group-containing alkoxysilane compound (A4); (B) water; and (C) inorganic hollow powders.