Abstract: An angular velocity detecting device which can estimate and detect correct mounting angles of a gyro sensor is achieved using outputs from the gyro sensor. The gyro sensor measures angular velocities in a sensor coordinate system and outputs them to an angular velocity calculating unit. A bias component removing unit of the angular velocity calculating unit carries out time average processing of the sensor coordinate system angular velocities, divides the sensor coordinate system angular velocities by time average values, and outputs them to a misalignment angle estimating unit. The misalignment angle estimating unit calculates, during a period in which a movable body is turning, a roll direction misalignment angle ?? using an angular velocity ?yse in a pitch angle ? direction and an angular velocity ?zse in a heading ? direction in the sensor coordinate system.