Disclosed are: a battery which is equipped with a power generation part having a sulfur-containing material contained therein, and a discrimination part of which the color is changed upon the chemical reaction with hydrogen sulfide, wherein both the parts are placed in an outer case, and wherein the discrimination part is so arranged as to be visible outside the outer case; and a battery which is equipped with a power generation part placed in an outer case and having a sulfur-containing material contained therein, and a discrimination means of which the color is changed at least partly upon the chemical reaction with hydrogen sulfide and is placed in a part of the outer case. In the batteries, the occurrence of the generation of hydrogen sulfide in the batteries can be discriminated readily and the presence or absence of deterioration of the batteries can be determined without destructuring the batteries by confirming the presence or absence of the change in color by means of the discrimination part or the discrimination means.