To solve the problem that a conventional measurement using a testing paper is difficult to measure a change in color by using transmitted light from a spectrophotometer since a paper is used as an adsorbent of an indicator and a detection reagent, that for the same reason, the indicator and the detection reagent ooze out of the testing paper during the measurement, thereby potentially causing a measurement error, and that a liquid indicator and a liquid detection reagent make a risk of liquid leakage when they are carried and used.

The indicator or the detection reagent is enclosed in a capsule which is insoluble in a specimen and permeable to a substance to be measured, thereby causing a reaction to occur in the capsule.