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, R
1
represents optionally substituted lower alkyl and the like, R
2
represents optionally substituted lower alkyl and the like, R
3
represents the formula (II):
(wherein, n represents 0 or 1, R
3a
represents a hydrogen atom and the like, R
3b
represents a hydrogen atom and the like, and R
3c
represents a hydrogen atom and the like) and the like, Q represents a hydrogen atom and the like, and W
1
represents a nitrogen atom and the like, W
2
represents a nitrogen atom and the like]