According to one embodiment, a voice synthesizing device includes a first operation receiving unit, a score transforming unit, and a voice synthesizing unit. The first operation receiving unit configured to receive a first operation specifying voice quality of a desired voice based on one or more upper level expressions indicating the voice quality. The score transforming unit configured to transform, based on a score transformation model that transforms a score of the upper level expression into a score of a lower level expression which is less abstract than the upper level expression, the score of the upper level expression corresponding to the first operation into a score of one or more lower level expressions. The voice synthesizing unit configured to generate a synthetic sound corresponding to a certain text based on the score of the lower level expression.