Abstract: A simplified training device for improving the batting skill of a batter in baseball, has a pair of arm cuffs adapted to encircle the arms of the batter at a location above the elbows thereof, and a pair of elongate flexible tie straps which are coextensive with each other and which extend between and are connected to the arm cuffs. The device is so constituted that the tie straps can be easily adjusted as to their effective lengths. When the tie straps are taut, they positively limit the maximum space between the arm cuffs at the time that the batter's arms are in a raised, retracted position. The straps are flexible and capable of collapsing movement to enable the arm cuffs to approach each other as the batter's arms are swung from the raised, retracted position toward the extended, ball-striking position.