A detection device for a two-wheeled vehicle is used for detecting the motion of the front and rear wheel interlocking braking system loaded on the two-wheeled vehicle which is provided with an anti-lock braking system. The device includes: a pair of front wheel bearing rollers, which bear the front wheels of the two-wheeled vehicle, have axis configured in parallel and rotate freely; a pair of rear wheel bearing rollers, which bear the rear wheels of the two-wheeled vehicle, have axis configured in parallel and rotate freely; a rotary speed measuring mechanism, which is respectively connected to a front wheel bearing roller and a rear wheel bearing roller, and measures the rotary speed of the front wheel and the rear wheel by each roller; a computing mechanism; and a judging mechanism, which judges whether the difference of two peak values obtained by the computing mechanism is within the prescribed limit.