A Wnt signaling inhibitor which comprises, as an active ingredient, a fused-ring heterocyclic compound represented by the following formula (IA) or a pharmaceutically acceptable salt thereof, and the like are provided:(wherein, n1A represents 0 or 1； n2A and n3A may be the same or different, and each represents 1 or 2； R0A represents optionally substituted aryl or the like； R2A represents a hydrogen atom or the like； R3A represents an optionally substituted aromatic heterocyclic group or the like； X1A, X2A, X3A and X4A each represent CH or the like； Y1A represents CH2 or the like； Y2A represents N or the like； and LA represents CH2 or the like) .
