A frequency band extending device comprising: signal dividing means configured to divide an input music signal into a plurality of sub-band signals; feature amount calculating means configured to calculate feature amount which expresses a feature of said input music signal using at least one of said plurality of sub-band signals divided by said signal dividing means, and said input music signal; high frequency sub-band power estimating means configured to calculate an estimated value of a high frequency sub-band power that is the power of a sub-band signal having a higher frequency band than said input music signal based on said feature amount calculated by said feature amount calculating means; and high frequency signal component generating means configured to generate a high frequency signal component based on said plurality of sub-band signals divided by said signal dividing means, and the estimated value of said high frequency sub-band power calculated by said high frequency sub-band power estimating means; wherein the frequency band of said input music signal is extended using said high frequency signal component generated by said high frequency signal component generating means; wherein said high frequency sub-band power estimating means is configured to calculate the estimated value of said high frequency sub-band power based on said feature amount, and a coefficient for each high frequency sub-band obtained beforehand by learning; and wherein said coefficient for each high frequency sub-band is generated by performing clustering of the residual vector of said high frequency signal component calculated with the coefficient for each high frequency sub-band obtained by regression analysis with a plurality of teacher signals, and performing regression analysis, for each cluster obtained by said clustering, using said teacher signals belonging to said cluster. signal dividing means configured to divide an input music signal into a plurality of sub-band signals; feature amount calculating means configured to calculate feature amount which expresses a feature of said input music signal using at least one of said plurality of sub-band signals divided by said signal dividing means, and said input music signal; high frequency sub-band power estimating means configured to calculate an estimated value of a high frequency sub-band power that is the power of a sub-band signal having a higher frequency band than said input music signal based on said feature amount calculated by said feature amount calculating means; and high frequency signal component generating means configured to generate a high frequency signal component based on said plurality of sub-band signals divided by said signal dividing means, and the estimated value of said high frequency sub-band power calculated by said high frequency sub-band power estimating means; wherein the frequency band of said input music signal is extended using said high frequency signal component generated by said high frequency signal component generating means; wherein said high frequency sub-band power estimating means is configured to calculate the estimated value of said high frequency sub-band power based on said feature amount, and a coefficient for each high frequency sub-band obtained beforehand by learning; and wherein said coefficient for each high frequency sub-band is generated by performing clustering of the residual vector of said high frequency signal component calculated with the coefficient for each high frequency sub-band obtained by regression analysis with a plurality of teacher signals, and performing regression analysis, for each cluster obtained by said clustering, using said teacher signals belonging to said cluster.