The present invention provides an inexpensive range image sensor and etc. A range image sensor comprises diffractive optical elements and on which are formed diffractive gratings that change a traveling direction of incident parallel light so that in a coordinate space defined by a xyz-axis, the incident parallel light is split into split beams, and angles formed by the x-axis and line segments determined by projected light spots formed by the split beams on a predetermined projection plane intersecting the z-axis become predetermined angles. Furthermore, the range image sensor is provided with a distance determining unit for determining distances to the projected light spots on the basis of the tilting with respect to the x-axis of the line segments determined by the projected light spots formed on the object by the split beams.