Apparatus and method for transmitting using multi-round contention

A transmission device and a method using a multi-stage contention are provided to improve a production yield and equality with respect to the use of channels of each user. A contention window initializing and backoff counter setting unit(100) initializes a contention window value of each stage, and sets a random backoff counter value of each stage. A backoff counter subtracting unit(102) reduces a backoff counter value of a corresponding stage by slot time. A comparing unit(104) checks whether or not the reduced backoff counter value is 0, and whether or not the corresponding stage is a final contention stage, and outputs a backoff counter value 0 of the final contention stage to a data transmission unit(108). When the backoff counter value 0 of the final contention stage is received, the data transmission unit transmits data to a reception side.