This invention includes: a voice quality feature database (101) holding voice quality features; a speaker attribute database (106) holding, for each voice quality feature, an identifier enabling a user to expect a voice quality of the voice quality feature; a weight setting unit (103) setting a weight for each acoustic feature of a voice quality; a scaling unit (105) calculating display coordinates of each voice quality feature based on the acoustic features in the voice quality feature and the weights set by the weight setting unit (103); a display unit (107) displaying the identifier of each voice quality feature on the calculated display coordinates; a position input unit (108) receiving designated coordinates; and a voice quality mix unit (110) (i) calculating a distance between (1) the received designated coordinates and (2) the display coordinates of each of a part or all of the voice quality features, and (ii) mixing the acoustic features of the part or all of the voice quality features together based on a ratio between the calculated distances in order to generate a new voice quality feature.