Box Collider not staying on the cylinder(gameobject) and falls when we add rigidbody component to it

Colldier is falling of the game object sword when I run the game this is happening after I have added rigid body component to the sword(cylinder) here are its image reviews49589-before.jpg


here is the preview of collider before game play

,The first one is the preview before the game play the collider is on the sword of the player which is a cylinder but when I start the game it falls off, even I have frozen its rotation tooo 49589-before.jpg

and then after when the gameplay starts the collider of the sword falls down

have you unchecked the gravity in rigidbody panel ?