PURPOSE: To suppress expansion of the end portions of a negative plate so as to prevent any contact between the negative plate and a positive plate by using a negative plate formed using an expanded grid as well as a mat-like separator and making the end portions of the separator touching the cut ends of the negative plate impermeable to electrolyte.

CONSTITUTION: A sealed lead storage battery is consituted by using an expanded grid for a negative plate and interposing a mat-like separator 9 made of glass fiber between a positive plate and the negative plate. The surface of the belt-like end portion of the separator 9 touching the cut end of the negative plate is made impermeable to electrolyte by being coated and solidified with a denatured polypropylene resin 8. The above coating may be performed with another resin, adhesive, tape or the like instead of the resin 8. The width of the end portions of the separator 9 coated and solidified with the resin 8 is adjusted to be at least 1/4 and smaller than 1/2 of the lateral dimension of the mesh of the end portions of the expanded grid of a negative plate so that these areas have impermeability to electrolyte. By the means mentioned above, expansion of an active material existing in the end portions of the negative plate is suppressed, thereby preventing any short circuits which might be caused between a positive plate and the negative plate.