Provided are a method for determining a valid subframe for cell in a non-licensed band in a wireless communication system, and a wireless apparatus using the method. The method comprises: determining whether all orthogonal frequency division multiplexing (OFDM) symbols of the cell are usable; and when all of the OFDM symbols of the subframe are usable, determining whether the subframe is a valid subframe based on whether a channel state information-reference signal (CSI-RS) resource is present in the subframe.