The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for reporting an radio link problem in the wireless communication system, the method comprising: receiving an indicator indicating which cell is a first cell of the second BS from either the first BS or the second BS; detecting a radio link problem on a cell belonging to the second BS; and reporting the radio link problem of the second BS to the first BS if the cell, on which the radio link problem is detected, is indicated as the first cell by the indicator.