To provide a catalyst for piezo-electric exhaust emission control, in which the catalyst can be surely activated, and the catalyst activation can be realized even from a relatively low temperature.

The catalyst for the piezo-electric exhaust emission control has a layered structure in which a piezo-electric element layer 10 containing a piezo-electric material, and a catalyst layer 20 containing catalyst species to activate an electric charge transfer are layered. It is arranged in the system varying in the pressure of the atmosphere. The catalyst for the exhaust emission control is provided with an electric charge supply means 30 to supply the electric charge generated in the piezo-electric element layer 10 to the catalyst layer 20.