The present specification relates to an apparatus and method for performing random access. This specification discloses a method for performing random access by a terminal in a non-terrestrial network system, the method comprising the steps of: performing a search for a cell of a non-terrestrial network on the basis of a synchronization signal block transmitted from a non-terrestrial network node; after the search for the cell is completed, receiving, from the non-terrestrial network node, random access-related information about the cell of the non-terrestrial network; generating a random access preamble on the basis of a frequency resource area of a random access channel related to the cell of the non-terrestrial network; and transmitting the generated random access preamble to the non-terrestrial network node. Performance degradation can be reduced when random access is performed in a non-terrestrial network system.