To provide a crack-inducing joint filler which secures a required cross sectional defective rate corresponding to the wall thickness of a concrete structure, without causing problems in manufacturing and storing.

A splicing projection 13a which constitutes a connection 13 of a base component 11 is connected to a splicing recess 13b which constitutes a connection of a connection component 12, so that splicing is performed. Alteration of the combination of the base component 11 and the connection component 12 allows a cross sectional defective rate corresponding to the wall thickness of a concrete structure to be easily secured, using small varieties. In the case that a crack is induced, water is cut off by a water cutoff component 18 due to the adhesion of the water cutoff component 18 to concrete, so that a reinforcement bar 4 is prevented from being corroded by immersion. This secures a required cross sectional defective rate corresponding to the wall thickness of a concrete structure, avoiding a problem requiring new equipment in manufacturing or a problem in storing such as increase in variety, with unitization.