an aligning and thickness measuring unit 112 and a thickness information collecting unit 114 the vein authentication unit 120 includes a vein pattern extracting unit 122 a vein pattern matching unit 124 and a storage unit 126 some of these plural blocks can be aggregated into one single block alternatively at least one of the plurality of blocks can be further segmented into a plurality of sub blocks the vein sensor unit 102 is equipped with a camera which captures the image of the palm held over the vein sensor unit 102 in accordance with an instruction of the image capturing unit 106 the vein sensor unit 102 captures the images of the palm at least twice on the basis of the instruction of the image capturing unit 106 capturing a plural number of times intends to observe the time based variation of the thickness of the vein the vein sensor unit 102 can capture the veins of the palm the operation unit 104 accepts an input of user 39 s identifying information such as a user 39 s id number from the user the operation unit 104 can be constructed of an operation panel like e g a keyboard a touch panel and a card reader the operation unit 104 is installed in a position lower than a position of the vein sensor unit 102 the operation unit 104 can be installed in the position lower than a position of a heart of the user the vein sensor unit 102 can be installed in a position higher than the position of the heart of the user further the operation unit 104 may also be installed in the position higher than the position of.