A device according to a mode of the present invention comprises optical mechanisms for guiding light from alight source to a tissue of a skin and scanning the same； a control calculation unit controlling the driving of optical mechanisms, acquiring a tomographic image of the skin by an optical interference signal generated by a processing optical system, and calculating a blood vessel network based on the tomographic image； and a display device displaying an image of the vascular network. The control calculation unit sets a reference profile in which a luminance profile in the depth direction of the obtained tomogram is functionally approximated, calculates the difference between the luminance value on the reference profile and the actual luminance value with respect tp the luminance value in the depth direction in the tomographic image as the outlier value V, specifies a coordinate having outlier V in a predetermined blood vessel determination range as a blood vessel or a blood vessel candidate, and calculates a blood vessel network.本發明一態樣的裝置係具備：光學機構，係用以使來自光源的光導向皮膚的組織並進行掃描；控制演算部，係控制光學機構的驅動，藉由處理光學系統而產生的光干涉信號來取得皮膚的斷層影像，並根據該斷層影像來算出血管網；及顯示裝置，係顯示血管網的影像。控制演算部係設定對所取得之斷層影像的深度方向的亮度明暗分佈特性予以函數近似所得的基準明暗分佈特性，就斷層影像的深度方向的亮度值，算出基準明暗分佈特性上的亮度值與實際的亮度值之差作為偏離值V，對預設的血管判定範圍中具有偏離值V的座標予以具體指定為血管或血管候補，而算出血管網。
