The ring-fused heterocyclic compound or a pharmaceutically acceptable salt thereof according to the present invention has a T-type calcium channel regulatory effect, and is useful, for example, as a medicament for treating and/or preventing pruritus. The present invention provides a ring-fused heterocyclic compound represented by the following general formula (I) or a pharmaceutically acceptable salt thereof and the like which has a T-type calcium channel regulatory effect and is useful as a therapeutic and/or preventive agent for pruritus, and the like. [wherein, R1 represents optionally substituted lower alkyl and the like, R2 represents optionally substituted lower alkyl and the like, R3 represents the formula (II): (wherein, n represents 0 or 1, R3a represents a hydrogen atom and the like, R3b represents a hydrogen atom and the like, and R3c represents a hydrogen atom and the like) and the like, Q represents a hydrogen atom and the like, and W1 represents a nitrogen atom and the like, W2 represents a nitrogen atom and the like].