Warning device and cabinet using same

A cabinet, comprising:

• a case comprising two opposite sidewalls and defining an opening, each of the sidewalls comprising a stage facing to the opening, one of the stages of the two sidewalls defining a receiving slot;
• a warning device received in the receiving slot, and comprising:
• a main body comprising a first end surface and a second end surface opposite to the first end surface, the main body defining a receiving room penetrating through the first end surface and the second end surface;
• a touching switch received in the receiving room and comprising two spaced pins, an operation pole, and a metal sheet, the operation pole positioned between the two spaced pins, one end of the operation pole protruding out of the first end surface, the metal sheet positioned on another end of the operation pole and connected between the two pins;
• and
• a pressure element comprising an operation portion and a pressure portion, one end of the operation portion connected to the pressure portion, another end of the operation portion positioned on the first end surface, the operation portion being above the operation pole;
• and
• a cover configured for closing the opening, wherein when the cover closes the opening, the cover presses the pressure portion of the pressure element, the operation pole is pushed by the operation portion so as to separate the metal sheet from the two spaced pins.