It is intended to provide a drug which is efficacious against pathological conditions relating to arginine-vasopressin V1b receptor. More particularly speaking, it is intended to provide a drug which has a therapeutic or preventive effect on depression, anxiety, Alzheimer's disease, Parkinson's disease, Huntington's chorea, eating disorders, hypertension, digestive diseases, drug addiction, epilepsy, brain infarction, brain ischemia, brain edema, head injury, inflammation, immune diseases, alopecia and so on. As the results of intensive studies, a novel 1,3-dihydro-2H-indol-2-one compound and a pyrrolidin-2-one compound fused with a heteroaromatic ring, which are highly selective antagonists of arginine-vasopressin V1b receptor, have high metabolic stabilities and show favorable brain penetration and high plasma concentrations, are found, thereby achieving the above objective.