Disclosed are a method for transmitting a random access preamble in a wireless communication system supporting a narrowband-Internet of things (NB-IoT) and an apparatus therefor. Specifically, the method performed by the terminal may include: receiving, from a base station, first configuration information for a first random access preamble and second configuration information for a second random access preamble; transmitting, to the base station, the first random access preamble by using the first configuration information; and transmitting, to the base station, the second random access preamble based on the second configuration information, when transmission of the first random access preamble satisfies a predetermined criterion, in which any one of the first random access preamble and the second random access preamble may be generated based on a sequence in which all elements are not configured to 1.