The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and a device for a terminal to transmit an uplink signal according to a normal HARQ operation in a wireless communication system supporting a carrier merge, the method comprising the steps of: forming a first cell set with a FDD and a second serving cell set with a TDD; receiving a PHICH signal from a subframe #(n−m−p) of the first serving cell, or receiving a PDCCH signal from a subframe #(n−m) of the first serving cell; and transmitting a PUSCH signal from a subframe #n of the second serving cell, in correspondence to the PHICH signal or the PDCCH signal, wherein n is an integer greater than or equal to 0, m is an integer greater than or equal to 1, and p is an integer greater than or equal to 1.