An angular velocity calculating device adapted to average an angular velocity signal (Ω) output from a gyro while a vehicle is stationary and to calculate an offset value (Ω OFF) and to cancel the offset value from an angular velocity signal output while the vehicle is running to output angular velocity, the angular velocity calculating device comprising: an angular velocity averager configured to calculate an average value of the angular velocity signal from the gyro at predetermined time intervals; an angular velocity storage configured to store the average angular velocity output from the angular velocity averager; the angular velocity calculating device characterized by comprising: a stationary range determiner configured to detect a minimum value (Ω MIN) and a maximum value (Ω MAX) of the angular velocity signal for a predetermined period T1 while the vehicle is stationary to determine thresholds of a range (TH1, TH2) of the angular velocity signal on the basis of which the vehicle is considered to be stationary; a stopping/running determiner configured to determine that the vehicle starts running when the angular velocity signal from the gyro exceeds the range and to determine that the vehicle is stationary when the angular velocity signal from the gyro is within the range; and an offset value determiner configured to determine the angular velocity, having been stored a set time (Ta) before a running start detection time (ts) detected by the stopping/running determiner, as the offset value. an angular velocity averager configured to calculate an average value of the angular velocity signal from the gyro at predetermined time intervals; an angular velocity storage configured to store the average angular velocity output from the angular velocity averager; the angular velocity calculating device characterized by comprising: a stationary range determiner configured to detect a minimum value (Ω MIN) and a maximum value (Ω MAX) of the angular velocity signal for a predetermined period T1 while the vehicle is stationary to determine thresholds of a range (TH1, TH2) of the angular velocity signal on the basis of which the vehicle is considered to be stationary; a stopping/running determiner configured to determine that the vehicle starts running when the angular velocity signal from the gyro exceeds the range and to determine that the vehicle is stationary when the angular velocity signal from the gyro is within the range; and an offset value determiner configured to determine the angular velocity, having been stored a set time (Ta) before a running start detection time (ts) detected by the stopping/running determiner, as the offset value. a stationary range determiner configured to detect a minimum value (Ω MIN) and a maximum value (Ω MAX) of the angular velocity signal for a predetermined period T1 while the vehicle is stationary to determine thresholds of a range (TH1, TH2) of the angular velocity signal on the basis of which the vehicle is considered to be stationary; a stopping/running determiner configured to determine that the vehicle starts running when the angular velocity signal from the gyro exceeds the range and to determine that the vehicle is stationary when the angular velocity signal from the gyro is within the range; and an offset value determiner configured to determine the angular velocity, having been stored a set time (Ta) before a running start detection time (ts) detected by the stopping/running determiner, as the offset value.