To provide a vehicle capable of largely taking adjustment width of attenuation force even when a detection member is arranged at the inside of a suspension device.

The motorcycle 1 (vehicle) is provided with a right side front fork 10a including an attenuation mechanism 17 provided between a front wheel 8 and a vehicle body and attenuating force in a stretching direction when the front wheel 8 and the vehicle body are relatively moved; a sensor part 18e arranged at the inside of the right side front fork 10a and detecting the expansion/contraction state when the front wheel 8 and the vehicle body are relatively moved; a detection device 18 including a body part 18b and a flange part 18a provided on the body part 18b; and an O ring 28 arranged between an inner surface of the right side front fork 10a and the detection device 18 and suppressing an oil at the inside of the right side front fork 10a from flowing out to the outside through a predetermined portion of the detection device 18.