A switch with light emitting function is provided. The switch is disposed on a circuit board for starting a device, and includes a case, a button, a light emitting diode (LED) and a number of pins. The button is protruded from the case. The LED is disposed inside the case, and has a positive end and a negative end. The pins are connected to a first electrical contact, a second electrical contact, a third electrical contact and the negative end of the LED, respectively. The positive end of the LED is electrically connected to the fourth electrical contact. When the button is pressed, the first electrical contact and the second electrical contact are shorted to start the device. Meanwhile, the third electrical contact and the fourth electrical contact are shorted, so that the LED is turned on to emit a light. No extra space is needed for disposing the LED.