A method for reporting a power headroom report, PHR, by a terminal in a mobile communication system supporting carrier aggregation, the method comprising: generating a Medium Access Control Protocol Data Unit, MAC PDU, including a MAC header and a payload, the MAC header including a sub-header and the payload including the PHR, wherein the sub-header includes a logical channel identifier, LCID, indicating that the PHR is a multiple entry PHR which is capable of reporting multiple power headrooms, PHs, and a length of the PHR, and the PHR includes information on the multiple PHs corresponding to multiple activated serving cells; and transmitting the MAC PDU to a base station; wherein a type II PH of a primary serving cell is included in the PHR in case that simultaneous physical uplink control channel, PUCCH, and physical uplink shared channel, PUSCH, is configured, and the type II PH of the primary serving cell is followed by a type I PH of the primary serving cell and one or more type I PH corresponding to one or more secondary serving cells, respectively in case that the type II PH is included in the PHR; the multiple PHs are included in ascending order of indices of the multiple activated serving cells in the PHR; the type II PH is a difference between a maximum transmission power of the terminal and an estimated power for a PUSCH and a PUCCH transmission and the type I PH is a difference between the maximum transmission power of the terminal and an estimated power for a PUSCH transmission; the PHR includes a bitmap indicating a presence of the type II PH of the primary cell and type I PHs for the one or more secondary serving cells in consecutive order, and two bits indicating a cell index of each of the one or more secondary serving cells are placed before corresponding type I PH for each of the one or more secondary serving cells, respectively. generating a Medium Access Control Protocol Data Unit, MAC PDU, including a MAC header and a payload, the MAC header including a sub-header and the payload including the PHR, wherein the sub-header includes a logical channel identifier, LCID, indicating that the PHR is a multiple entry PHR which is capable of reporting multiple power headrooms, PHs, and a length of the PHR, and the PHR includes information on the multiple PHs corresponding to multiple activated serving cells; and transmitting the MAC PDU to a base station; wherein a type II PH of a primary serving cell is included in the PHR in case that simultaneous physical uplink control channel, PUCCH, and physical uplink shared channel, PUSCH, is configured, and the type II PH of the primary serving cell is followed by a type I PH of the primary serving cell and one or more type I PH corresponding to one or more secondary serving cells, respectively in case that the type II PH is included in the PHR; the multiple PHs are included in ascending order of indices of the multiple activated serving cells in the PHR; the type II PH is a difference between a maximum transmission power of the terminal and an estimated power for a PUSCH and a PUCCH transmission and the type I PH is a difference between the maximum transmission power of the terminal and an estimated power for a PUSCH transmission; the PHR includes a bitmap indicating a presence of the type II PH of the primary cell and type I PHs for the one or more secondary serving cells in consecutive order, and two bits indicating a cell index of each of the one or more secondary serving cells are placed before corresponding type I PH for each of the one or more secondary serving cells, respectively.