A spiral scan is introduced to collect three dimensional (3D) data of the ocular region so that it may give uniformly-spaced echo data with enough resolution and that the cross-sectional image of any specified plane can be reconstructed. The system consists of a 3D-Scanning unit, an image processing unit with memories of 2M bytes, and a ultrasound puiser and receiver unit. The obtained 3D-data are stored on a floppy disk or directly in the large memory for fast processing. A conventional probe of 10 MHz is used to scan the total tissue and is driven spirally under the control of the 3D-Scanning unit. The developed system can supply black and white 3D-images with or without the pseudo-color cross-section, gradated according to the echo levels, to allow quantitative and qualitative evaluation of the intraocular pathology. The shape and the contour image from the desired viewing angle can be implemented by the built-in microcomputer. The present system was assessed by case studies to be qualified as to contain more information as compared with the ordinary B-mode echography and the rapid image processing to be useful in clinical routine activities. Measurement of the volume is another function of the 3D echography which is not obtainable by the conventional B-mode. The precision was experimented by the measurement of the lens volume.