An apparatus and method for receiving control information transmitted from a transmitter using one of a plurality of slot lengths in a high-speed packet transmission mobile communication system is provided. The apparatus and method includes a decoder adapted to receive symbols by the slot, and generate at least one bit stream by decoding as many symbols of at least one possible slot length among a plurality of slot lengths according to a previous decoding result. An error checker adapted to perform error checking on the bit stream from the decoder. A controller is adapted to provide symbols of one more consecutive slot to the decoder, if the error checking failed, and acquire control information from the error checking-passed bit stream, if the error check passed. The decoder is further adapted to output at least one frame quality metric for the bit stream along with the bit stream. If the number of error checking-passed bit streams is larger than or equal to 2, the controller compares frame quality metrics for the bit streams and selects one bit stream having the maximum frame quality metric in order to acquire the control information.