A windscreen attaching/detaching device includes a mount bracket including a stopper and a hook, with the mount bracket secured to a windscreen and a mount stay including a damper member and a lock mechanism, with the mount stay secured to a vehicle body. The lock mechanism urges the hook to a locked position. The lock mechanism includes an arm disengaging with the hook and a lever linking to the arm and turnable between the locked position and an unlocked position. The windscreen engages the damper member with the stopper as well as engages the arm with the hook to turn the lever to the locked position that allows the windscreen to be secured to the vehicle body.