To provide a sealer composition for root canal filling consisting of a liquid material containing a polymer (a) of an acid group-containing polymerizable monomer in which a portion or the entirety of the acidic group in a molecule forms a salt with an alkaline metal and water (b), wherein the pH of the liquid material is in the range from 3.5 to 5.5, and a powder material containing an acid reactive inorganic powder (c), wherein, a cured product of a kneaded material of the liquid material and the powder material comprises 3 to 20 part by weight of the polymer (a), 10 to 60 part by weight of the water (b), and 30 to 85 part by weight of the acid reactive inorganic powder (c).