In an acceleration estimation device for estimating acceleration of a vehicle, a Karman filter for constant speed estimates x-direction acceleration offset and z-direction acceleration offset when a motorcycle is stopped and is traveling at a constant speed. An offset corrector corrects an x-direction acceleration and a z-direction acceleration on the basis of an x-direction acceleration offset estimated value and a z-direction acceleration offset estimated value when the motorcycle is accelerated and decelerated. A Karman filter for acceleration/deceleration estimates the pitch angle of a vehicle body on the basis of a wheel speed and the corrected x-direction acceleration and z-direction acceleration when the motorcycle is accelerated and decelerated. An acceleration corrector obtains an X-direction acceleration and a Z-direction acceleration on the basis of the estimated pitch angle and the corrected x-direction acceleration and z-direction acceleration. A vehicle speed operation unit integrates over time the X-direction acceleration to calculate an X-direction speed.