Provided is an audio processing device and method, in which sound can be more efficiently reproduced. An audio processing device includes a matrix generation unit which generates a vector for each time-frequency with a head-related transfer function obtained by spherical harmonic transform by spherical harmonics as an element by using only the element corresponding to a degree of the spherical harmonics determined for the time-frequency or on the basis of the element common to all users and the element dependent on an individual user, and a head-related transfer function synthesis unit which generates a headphone drive signal of a time-frequency domain by synthesizing an input signal of a spherical harmonic domain and the generated vector.