Provided are a plasma generating apparatus and a substrate treating apparatus. The plasma generating apparatus includes a plurality of ground electrodes arranged inside a vacuum container and extending parallel to each other and power electrodes arranged between the ground electrodes. An area where a distance between the ground electrode and the power electrode is constant exists, and the power electrodes are tapered in a direction facing the substrate. The power electrodes are connected to an RF power source, and height of the power electrode is greater than that of the ground electrode in the direction facing the substrate.