Juvenile idiopathic arthritis (JIA) is a systemic inflammatory disease of childhood onset. The purpose of this study was to clarify the frequency of adverse events caused by drugs used in JIA treatment and characterize their safety profiles using a spontaneous reporting system database. We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database. Adverse event reports on drugs used for the treatment of JIA and which were submitted to the Pharmaceuticals and Medical Devices Agency were analyzed, and the reporting odds ratio (ROR) and 95% confidence interval (CI) for reports on each adverse event were calculated. A total of 5,748 reports were identified in the treatment of JIA, in which 35 different drugs were involved. Adverse events by drugs in JIA were frequently reported in females (64.3%) and in those younger than 10 (61.2%). Among the most frequently reported drugs, prednisolone (36.8%) and tocilizumab (36.0%) were predominant. Prednisolone was significantly correlated with hematophagic histiocytosis (ROR, 1.37; 95% CI, 1.18 - 1.61). Tocilizumab was associated with a high ROR for pneumonia (ROR, 8.61: 95% CI, 5.81 - 12.7), a decreased neutrophil count (ROR, 6.1; 95% CI, 4.07 - 9.16), and lymphadenitis (ROR, 8.34; 95% CI, 4.2 - 16.6). Our results revealed the safety profile of drugs for the treatment of JIA patients. It was suggested that there is a diversity in drugs and their strength of association with adverse events in JIA patients. Our results may provide useful information for the treatment of JIA patients, although further research with more data is needed.