To provide a two-paste type sealer composition for root canal filling consisting of a first paste 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, a non-acid reactive powder (b) and water (c), wherein the pH of the first paste is in the range from 3.5 to 5.5, and a second paste containing an acid reactive inorganic powder (d), water (c) and a thickener (e), wherein, a cured product of a kneaded material of the first paste and the second paste comprises 3 to 20 part by weight of the polymer (a), 15 to 60 part by weight of the water (c), and 30 to 70 part by weight of the acid reactive inorganic powder (d).