Disclosed is a circuit for supplying ear-microphone bias power in a mobile terminal that reduces power consumption due to unnecessary ear-microphone bias when the terminal is in a sleep mode with an ear/microphone being connected to the terminal through an ear-microphone line. The ear/microphone has a call switch connected to the ear-microphone line. The circuit receives first and second powers through first and second power input terminals, respectively. The first power is supplied when the terminal is not in the sleep mode, whereas the second power having a voltage lower than that of the first power is supplied also in the sleep mode. The circuit supplies ear-microphone bias power, based on the first power, to the ear-microphone line when not in the sleep mode, and supplies power for detecting a switching operation of the call switch, based on the second power, to the ear-microphone line in the sleep mode.