Abstract: In an electric circuit whose behavior is changed corresponding to a peripheral environment, an abnormality detection device can surely detect abnormality in the electric circuit even in a state where a value of the peripheral environment cannot be specified. An abnormality detection device according to the present invention detects abnormality in a detection circuit (112) which detects a specific kind of physical quantity. The abnormality detection device includes an abnormality detection part (220a) which changes magnitude of a power source voltage (Vcc?) which is supplied to the detection circuit (112), and detects abnormality in the detection circuit based on an output signal (Vo2) from the detection circuit at a power source voltage (Vc2) after the change.

Abstract: An apparatus for actuating a plurality of safety devices equipped in a vehicle for protecting occupants from an impact of a collision has a plurality of squibs (4,5) connected in series with each other so as to form a series circuit (6) and ignited by a current flowing through and conformed to one and the same standard. A power source (3) supplies electrical energy to the series circuit (6), and a collision detector (7) allows a current to flow from the power source (3) to said series circuit (6) when detecting a collision. A required energy for igniting all of the squibs (4,5) is thus supplied before the series circuit (6) opens electrically at one squib.