1. An image processing apparatus comprising: an obtaining unit for obtaining image data of a left eye image and a right eye image of a 3D content that has no black border inserted thereto, a black border width according to a parallax amount in a periphery of a right image frame between the left eye image and the right eye image, and a black border width according to a parallax amount in a periphery of a left image frame between the left eye image and the right eye image; and a generating unit for generating a border-attached left eye image and a border-attached right eye image by inserting an image having the obtained black border width according to the parallax amount in the periphery of the right image frame and an image having the obtained black border width according to the parallax amount in the periphery of the left image frame into the left eye image and the right eye image.