The invention discloses a vein imaging apparatus and a vein image interpolation method. An imaging element of the apparatus includes a vein image data generation region for generating image data of a vein based on a near-infrared light that was condensed by a lens array and that was scattered in the living body and transmitted through the vein, and a thermal noise output data generation region that includes a pixel shielded from light and generates a thermal noise output that is an output value output from the pixel shielded from light. The vein imaging apparatus measures thermal noise based on the thermal noise output data, and estimates an imaging temperature based on a measurement result. The vein imaging apparatus corrects the vein image data by changing a black level reference value based on estimated image temperature so as to generate vein images, and performs interpolation processing of the image based on the estimated temperature, wherein the black level reference value is an output value of data output from the imaging element when the imaging element images an image only in black color, and the change of the black level reference value includes multiplying the black level reference value at the normal temperature by a correction coefficient which is adjusted based on the imaging temperature.