Abstract: An electromechanical actuator has a stack composed of electromechanical elements, and an inactive element intervening in the stack to divide it into two sections. In a wire-dot printing head using the actuator, the stack sections are successively energized to increase a forward stroke of a printing wire for a high speed printing. In another aspect, an electromechanical actuator used in a wire-dot printer has a spring for regulating and braking a rearward stroke of a printing wire or a stopper such that the wire can be prevented from being moved back beyond an initial position. Alternatively, a stopper is incorporated to forcibly stop the wire at the initial position during the rearward stroke thereof. In yet another aspect, an electromechanical actuator has a stack composed of electromechanical elements, and the stack is supported by a block through a leaf spring securely joined therebetween to prevent generation of large stress in the stack.