The purpose of this study was to investigate the effect of singing exercises on the separation of the singing voice from the speaking voice. The subjects for this study were 5 years old children. Subjects were divided into two groups -a control group and an experimental group. Both groups practiced two songs- "Mary had a little lamb" and "Genkotsuyama-no-tanukisan" (a traditional Japanese children's song), 5 times in one day. The experimental group practiced for ten days, while the control group practiced only one day. Subjects were investigated for their speaking fundamental frequency and their starting pitches for singing without accompaniment. The vocalization of the subject's name was used as a speech sample to investigate the speaking fundamental frequency, and "Mary had a little lamb" and "Genkotsuyama-no-tanukisan" were selected as the songs to investigate the starting pitch. The differences between the speaking fundamental frequency and the starting pitches were used to examine whether subjects can separate their singing voice from their speaking voice. Results showed that the differences between the speaking fundamental frequency and starting pitches were significantly larger for the experimental group than to the control group. This findings suggests that singing exercises had an effect on the separation of the singing voice from the speaking voice.