To provide a material which can more easily detect an oxidizing gas.

An ink composition for detecting an oxidizing gas contains at least one type of azo dye, methine dye, triarylmethane dye, and thiazine dye. Furthermore, an ink composition for detecting an oxidizing gas contains a cationic surface active agent that is at least one type selected from among an alkyltrimethylammonium salt, an isoquinolinium salt, an imidazolinium salt, and a pyridinium salt.