There is provided a frameless display device in which a frame on the periphery of a display portion is made invisible. The frameless display device makes the frame on the top surface of a button 8 invisible to display an image on the entire surface of the button 8, wherein the button 8 has a lens 9 and a button cover 8A, wherein a display device 6 is provided below the lens 9, and wherein the lens 9 disposed on top of the button 8 includes a curved surface 9A formed on the periphery of the top surface of the lens 9, a depression formed on the bottom surface of the lens, a step formed at the periphery of the lens, and an inclined surface formed at the step and inclined towards the center of the lens 9.