Method for allowing terminal to transmit power headroom information in wireless communication system and device therefor

A user equipment (UE) with which a primary cell and at least one secondary cell are configured, for transmitting power headroom (PH) information in a wireless communication system, the UE comprising:

• a processor configured to generate the PH information;
• and
• a transmitter configured to transmit the PH information to a base station,
• wherein the PH information includes a first field including a plurality of indicators, each of the plurality of indicators indicating the presence of a second field indicating a PH level of a corresponding secondary cell, and
• wherein the PH information includes a type-2 PH field which is always included for the primary cell together with a type-1 PH field.