A light-guide device is provided for detecting and amplify the light emitted by indicator lamps of functional modules mounted in a chassis. The light-guide device includes a plurality of light-guide columns, a circuit board, and a plurality of light-guide blocks. The circuit board includes a plurality of amplifying circuits, each including a photosensitive diode and a plurality of light-emitting diodes (LEDs). One of the LEDs is lit when the photosensitive diode detecting the light emitted by the indicator lamp of one corresponding functional modules. The light-guide blocks guide lights emitted by the corresponding LEDs to an outside of the chassis.