1. A three-dimensional measuring device, comprising: an irradiation unit that has a light intensity distribution in a banded shape along a transport direction of an object to be measured and that can switch between and irradiate a plurality of types of pattern lights with differing brightness to the continuously transported object to be measured; an imaging unit that images a reflected light from the object to be measured irradiated with the various types of pattern lights and that outputs an image data including at least a brightness value; an image data acquisition unit that, each time the object to be measured is transported a predetermined amount, configures as one set image data in a plurality of ways imaged under the pattern light of the same brightness, a phase thereof changed a predetermined amount at a time, and that acquires a plurality of image data sets imaged under the plurality of types of pattern lights; a determination unit that determines whether or not a brightness value of each pixel in the image data corresponding to each coordinate position on the object to be measured is included within a predetermined effective range; an extraction unit that extracts an image data set with the brightness value of each of the pixels in the image data within the effective range from among the plurality of image data sets at each of the coordinate positions of the object to be measured; and a three-dimensional measurement unit that performs three-dimensional measurement relating to each of the coordinate positions of the object to be measured based on the extracted image data set; wherein the extraction unit extracts the image data set imaged under the pattern light with the highest irradiation brightness among the plurality of types of the pattern lights when there is a plurality of sets of the image data sets with the brightness value of each of the pixels in the image data within the effective range from among the plurality of the image data sets.