to each of the color shades 1 2 3 4 5 6 7 8 when uneven pattern 113 is at a determined position angle corresponding to each of the color shades converter switches k 1 k 2 k 3 k 4 are operated for example when the central area of each color shade and each color shade boundary comes into a display position in window 33 the code for that particular color or boundary is determined by the relationship of uneven pattern 113 to converter switches k 1 k 2 k 3 and k 4 which produces the four bit electric signal thus when a start key is depressed the input code for the converter switches k 1 k 2 k 3 k 4 turned on or off by the uneven pattern 113 is determined and read out by the electronic circuit section including the cpu housed within casing unit 1 the cpu then displays on display section 17 the significance of the color shade for example it displays a read out of a urine sugar level corresponding to the color shade or color shade border which best corresponds to the color of the color test paper 51 with the fig1 code section the four bit pattern does not change in regular binary order but instead the arrayed order of 34 0 34 to 34 f 34 varies fig9 shows an example of a four bit array generated by the uneven pattern 113 as shown by fig9 the four bit digital numbers from 34 0 34 to 34 f 34 are ordered at random the fig9 arrangement has the following binary signal order 0 2.