To provide a method of manufacturing a grill for a lead battery for allowing the avoidance and reduction of a problem of a cut in pattern of grill skeleton in an expanding machining apparatus without a drop in production efficiency.

In the manufacturing method, a lead alloy sheet 2, a preliminary expanding machining apparatus 3, a temperature controlled tank 4, and an expanding machining apparatus 5 are prepared. A boundary temperature for a cut in pattern with respect to a width for a nick in the sheet 2 is determined beforehand. On the preliminary expanding machining apparatus 3, a nick is next formed in the sheet 2 at a maximum nick width Lm of a grill to be manufactured. If there is no cut in pattern found in the preceding process, the sheet 2 is fed to the expanding machining apparatus 5. If there is a cut in pattern found, the sheet 2 is heated more than the boundary temperature in the temperature controlled tank 4. The sheet 2 is then fed to the expanding machining apparatus 5 to manufacture an expanded grill.