1. A music piece reproducing apparatus comprising: a sound collecting unit collecting noise data of an ambient environment; an analyzing unit performing a frequency analysis to the noise data collected by said sound collecting unit and extracting a feature amount showing a feature of said noise data; a noise parameter database classifying the noise data of at least one of a plurality of environments; and a reproducing unit reproducing music piece data which has been recorded in a recording medium and classified in at least one of a plurality of categories, wherein said analyzing unit classifies said noise data with reference to said noise parameter database on the basis of the extracted feature amount of said noise data, selects a previously-corresponded category of music pieces in accordance with a classification result of said noise data, selects predetermined music piece data from music piece data classified into said selected category, has a memory storing the classification result of said noise data a predetermined number of times, performs said classification to said noise data every predetermined time, and classifies said noise data on the basis of an average of the classification results of said predetermined number of times stored in said memory, and performs a convolution operation such that weight coefficients progressively decrease as the classification results of the predetermined number of times becomes older in time, and classifies said noise data on the basis of the average of the classification results of said noise data of said predetermined number of times to which said weight coefficients have been convolved.