There is provided a musical composition-reproducing device and a musical composition-reproducing method that make it possible to make the most of many sounding channels and are capable of imparting an effect to musical tones without providing a special effect circuit. Musical composition data read from a musical composition data file FL is read out as data of a track 1 comprised of 4 channels, and is also copied and read out as data of a track 2, a track 3 and a track 4. Delay times of delaying means D1 to D3 and attenuations of attenuating means G1 to G3 are determined as being values t1 to t3 and g1 to g3, respectively, in accordance with effect parameter information. A sequencer SQ reproduces three effect sounding sequence data in the tracks 2 to 4, which is delayed by the delay times t1 to t3 and attenuated by the attenuations g1 to g3, as an effect sound providing a reverberation to musical tones reproduced based on the sequence data in the track 1 by using 12 channels among 16 channels.