A sintered substrate is configured such that pores having a pore size (pore radius) of from 5 μm to 7 μm have a peak volume fraction with respect to the total pore volume of the sintered substrate, and pores having a pore radius of greater than 8.5 μm has a volume fraction of 11% or less with respect to the total pore volume of the sintered substrate. The sintered substrate has a smaller number of large-sized pores than conventional sintered substrates and a more uniform pore size distribution, and therefore shows a sufficient strength even when the porosity is increased. In addition, a cadmium negative electrode employing the sintered substrate shows excellent gas absorption capability and therefore can reduce the internal pressure of the battery during charge.