The stretcher comprises a frame with two stretch units mounted thereon for adjustment toward and away from each other for accommodating therebetween selected lengths of sheet or plate stock to be stretched or stretch formed. A male die is supported between the units when stretch forming is to be effected. Each unit comprises a linkage rockable by power means about a horizontal pivot extending transversely of the stock and tensioning dimension, and carries a stock gripping head. Rocking of the linkages causes the heads to swing about their pivots in directions away from each other for stretching the stock and toward the frame for laying the stock onto the die. The stretcher is characterized in that the horizontal pivot is adjustable along a path extending generally upwardly and downwardly normal to the plane of the stock, and the units can be latched securely in adjusted positions along the frame. With these adjustments, a preselected exact amount of total stretch can be imparted to the stock.