The invention provides an angular velocity sensor which is provided with a smoothing circuit having a large smoothing time constant so that it can be reduced in size and integrated into an IC. Smoothing circuit (9) is provided with first switch (11), first capacitor (12), second switch (13), second capacitor (17) and control signal feeding module (15). Control signal feeding module (15) feeds first switch (11) and second switch (13) with a signal for controlling ON/OFF. According to this configuration, an equivalently large smoothing time constant can be set by reducing the frequency of the switching control signal of control signal feeding module (15), even if the capacities of first capacitor (12) and second capacitor (17) are small. Especially in case the capacitors are integrated into an IC, their area of occupation can be reduced to reduce the size of the angular velocity sensor and integrate the same into the IC.