Inclusion Criteria:  Age: 19 - 79 years More than 3 months post stroke Functional ambulation classification (FAC) (1~4)  Exclusion Criteria:  History of serious neurological disease other than stroke Difficult to understand experimental tasks because of extremely severe cognitive impairment (Korean-Mini-Mental State Examination, K-MMSE≤10) History of psychiatric disease Contraindicated to tDCS