A random access apparatus for supporting a variety of access service classes includes a radio frequency (RF) transmitting/receiving unit for receiving a preamble introduction broadcasting signal from a base station and transmitting a random access preamble to the base station, an introduction broadcasting signal processing unit for extracting a random access usage relating to M-sequences and hadamard sequences from the received preamble introduction broadcasting signal, a selecting unit for selecting a plurality of M-sequences and a hadamard sequence corresponding to a random access purpose based on the extracted random access usage, and a preamble producing unit for generating the random access preamble using the selected plurality of M-sequences and the selected hadamard sequence.