The present invention provides a mortar tile which can reduce labor, time and cost required for installation without reducing a harmful substance decomposing ability using a photoresist. To achieve such an object, a mortar which is molded in a tile shape is manufactured by forming a formed article in a state that a photocatalyst is added to the mortar and, thereafter, the pressure-forming is performed at a pressure which allows the formation of open pores in a surface thereof, and a photocatalyst is applied to a surface of the formed article.