PURPOSE: To produce a mother's voice, her melodies and the like, or to drive the external functions of toys for promoting the sound sleep of a baby by detecting the baby's voice by a voice detecting means, and driving a voice regenerating means.

CONSTITUTION: A microphone 10 receives ambient sounds such as baby's voices (cries) to send the output to a filter circuit 11. The filter circuit 11 extracts only frequency components corresponding to the baby's cry from the voice signals received by the microphone 10 to send the output to an amplifying circuit 12. The first, second and third memory circuits 21, 23 and 24 consist of an ROM, memory card, etc., to store respectively different voice data. These voice data are melodies, etc., preselected to the tastes of babies from among a plurality of kinds of voice data. A regenerating circuit 22 converts the voice data outputted from any of the memory circuits 21, 23 and 24 to the voice signal to send the output to a switch circuit 25.