Abstract: A personal security device having a box holding a circuit board, a siren, a first jack, a battery holder, a second jack, a switch and a lamp, a control plug for connecting to the first jack to turn off the siren, the control plug being attached with a swivel hook for hanging a key-ring, and a plug and switch unit, the plug and switch unit including a plug for connecting to the second jack to turn off the siren, a switch assembly, and a cord connected between the plug and the switch assembly, the switch assembly of the plug and switch unit having a switch box, and two metal spring plates partially extending out of the switch box, the metal spring plates of the switch assembly turning off the circuit of the plug of the plug and switch unit when squeezed toward each other, or turning on the circuit of the plug of the plug and switch unit when released, the siren being triggered to produce an audio alarm signal when the control plug or the plug of the plug and switch unit is disconnected from the box.