1. A method for displaying three-dimensional integral images using a mask and a time division multiplexing; comprising: allowing element images 130 and 230 obtained from a three-dimensional object 110 to pass through a lenslet 220 and a mask 240 for thereby displaying a three-dimensional image 210 in a space, the mask 240 being formed of a blocking region 242 through which the element image 230 does not pass, and a transmission region 241 through which the element image 230 passes for thereby displaying a three-dimensional image.