An interdental cleaning tool comprising: a base portion made of a synthetic resin; and a soft portion made of an elastomer that covers at least a part of the base portion, the base portion including a handle base portion, and a core base portion that has an elongated shaft-shape and connects continuously to a tip end portion of the handle base portion, the soft portion having at least a cleaning soft portion that covers the core base portion, the handle base portion constituting a handle portion serving as a grip, and the core base portion and the cleaning soft portion which constitute a cleaning portion for interdental cleaning, wherein two or more cleaning portion recesses which penetrate the cleaning soft portion and form core base portion recesses in the core base portion are formed on each of a first side portion and a second side portion of the cleaning portion at an interval in an axial direction of the cleaning portion, wherein at least one set of the two cleaning portion recesses out of plural sets of the cleaning portion recesses pairing with each other between the first side portion and the second side portion are formed at an interval in the axial direction of the cleaning portion so as to be avoided from overlapping each other in a circumferential direction of the cleaning portion, and the at least one set of the cleaning portion recesses formed at the interval in the axial direction of the cleaning portion has, therebetween, an interval in the axial direction of the cleaning portion, the interval being set to one fourth or more of a maximum axial length of the cleaning portion recesses. a base portion made of a synthetic resin; and a soft portion made of an elastomer that covers at least a part of the base portion, the base portion including a handle base portion, and a core base portion that has an elongated shaft-shape and connects continuously to a tip end portion of the handle base portion, the soft portion having at least a cleaning soft portion that covers the core base portion, the handle base portion constituting a handle portion serving as a grip, and the core base portion and the cleaning soft portion which constitute a cleaning portion for interdental cleaning, wherein two or more cleaning portion recesses which penetrate the cleaning soft portion and form core base portion recesses in the core base portion are formed on each of a first side portion and a second side portion of the cleaning portion at an interval in an axial direction of the cleaning portion, wherein at least one set of the two cleaning portion recesses out of plural sets of the cleaning portion recesses pairing with each other between the first side portion and the second side portion are formed at an interval in the axial direction of the cleaning portion so as to be avoided from overlapping each other in a circumferential direction of the cleaning portion, and the at least one set of the cleaning portion recesses formed at the interval in the axial direction of the cleaning portion has, therebetween, an interval in the axial direction of the cleaning portion, the interval being set to one fourth or more of a maximum axial length of the cleaning portion recesses.