To provide a bat which is capable of allowing a mark to remain at the bat and easily eliminating the mark after checking the mark.

An air-containing hermitically sealed rubber long cylinder 2 the bottom of which is formed by bending is attached to the bat and the rear end of the rubber long cylinder 2 is fastened and fixed to the bat by building an inverted U-shaped fitting 4 vertically moving at its front into a U-shaped fitting 3. When the ball is struck by this bat, the air in the rubber long cylinder 2 of this struck part is compressed by the intensity of the collision force of the ball to give rise to movement and is streamed into the rear end in the cylinder, by which the front of the inverted U-shaped fitting 4 is pushed up and is confined and therefore the collision point of the ball loses the air pressure and remains by recessing, giving rise to the mark. When the inverted U-shaped fitting 4 is returned to the home position by pushing the same with the fingers, the air in the cylinder of the rubber long cylinder 2 is also pushed back into the original cylinder and the recessed part is built up and therefore the mark is easily and successively eliminated.