CATALYST DEVICE FOR LEAD-ACID BATTERY, AND LEAD-ACID BATTERY

Provided is a catalyst device for a lead-acid battery, the catalyst device being capable of reducing gas release from an electrolyte solution and a decrease in electrolyte solution due to the leakage, thus providing a lead-acid battery having a long life, and being capable of ensuring safety even in excessive flow of gas. Also provided is a lead-acid battery including the catalyst device. A catalyst device for a lead-acid battery, including: a catalyst layer including a catalyst to accelerate a reaction for generating water or water vapor from oxygen and hydrogen; and a porous membrane including thermoplastic resin having a melting point or a glass transition temperature of 160° C. or less, and wherein at least one surface of the catalyst layer is in contact with the porous membrane, and the porous membrane has a planar size being equal to or greater than that of the catalyst layer. Also a lead-acid battery including the catalyst device.