In this paper, a single-degree-of-freedom robot for assisting ophthalmologic surgery is proposed. A soft linear actuator drives the robot, and a needle attached to the tip punctures the cornea. The soft actuator has low friction and generates less stick slip, and there is no backlash since it does not require reduction gears. It can be controlled more precisely than conventional robots using electric motors or pneumatic cylinders. We conducted a cornea penetration experiment and measured the changes in intraocular pressure during intraocular injection using the proposed device.