A shaking amount detecting apparatus includes an angular velocity sensor that detects yaw, pitch, and roll-angular-velocities, an acceleration sensor that detects X and Y-accelerations in X and Y-axis directions, radius calculating sections that respectively calculate a yaw-radius and an XZ-roll-radius on the basis of a yaw-angular-velocity, a roll-angular-velocity, and an X-acceleration at different times, a velocity calculating section that multiplies the yaw-angular-velocity with the yaw-radius to calculate a first component of an X-velocity, a velocity calculating section that multiplies the roll-angular-velocity with the XZ-roll-radius to calculate a second component of the X-velocity, an adding section that adds up the first component of the X-velocity and the second component of the X-velocity to acquire the X-velocity, and an integrating section that integrates the X-velocity with respect to a time period to thereby calculate a movement amount in the X-axis direction.