1. A human hand posture estimating device comprising at least one computer including at least one processor, the at least one computer comprising: a hand image acquiring section that acquires a first hand image; a shape data calculating section that calculates first shape data relating to vertical and horizontal sizes of the first hand image; an image characteristic amount extracting section that extracts a first image characteristic amount of the first hand image; a collation section that reads, from a database holding a plurality of data sets each having a set of angle data of a finger, second shape data relating to vertical and horizontal sizes of a second hand image of the hand, the second shape data in a predetermined data set, and collates the second shape data with the first shape data to form a first collated data set smaller than the predetermined data set that contains second shape data matched in collation with the first shape data; and an estimation section that collates a second image characteristic amount of the second hand image in the first collated data set with the first image characteristic amount to estimate a human hand posture of the first hand image, wherein the collation section collates the first hand image with the second hand image based on a difference between the first shape data and the second shape data, and wherein the shape data includes a first shape ratio obtained from a total number of vertical pixels of the hand image and a total number of horizontal pixels thereof, and a second shape ratio obtained based on a positional relation between a predetermined base pixel in the hand image and a pixel of an outer end of the hand image.