Disclosed is a root canal filler for non-extracted tooth which causes no internal resorption or external resorption in a tooth with complete root formation, shows no odontoclast, and contributes to the regeneration of a dental tissue in which odontoblasts are smoothly aligned on the dentin wall. After pulpectomy or enlargement/cleaning of an infected root canal, a root canal filler for non-extracted tooth, which comprises tooth pulp stem cells and an extracellular matrix, is inserted into the apical side of the root canal of the non-extracted tooth. The tooth pulp stem cells may be, for example, dental pulp CXCR4-positive cells. It is preferred to attach, to the crown side of the root canal, migration factor(s) including at least one factor selected from among a cell migration factor, a cell proliferation factor, a neurotrophic factor and an angiogenic factor.