A rectangular secondary battery comprising: an electrode body that includes a plurality of stacked electrode plates (20,30); a rectangular outer casing that has an opening and that accommodates the electrode body; a cover plate that seals the opening and that is provided with an external terminal (18,19) on a side opposite to a side of the electrode body; and a collector terminal that is electrically connected to the external terminal (18,19) and that is disposed inside the rectangular outer casing, wherein each electrode plate (20,30) includes an active material arrangement portion and a collector tab, the active material arrangement portion including a plate-like core body and an active material containing layer that is provided at the core body, the collector tab being integrated with the core body and protruding from the active material arrangement portion, wherein each collector tab includes a curved portion and an end (22b,22c), the curved portion being positioned between the active material arrangement portion corresponding thereto and the collector terminal in a height direction of the rectangular outer casing and having at least a part thereof curved, the end (22b,22c) being positioned at the curved portion on a side opposite to a side of the active material arrangement portion, and wherein each end (22b,22c) includes a joint portion that is joined and electrically connected to the collector terminal; characterized in that the collector tabs that are included in the plurality of electrode plates (20,30) are disposed so as to overlap each other and constitute a tab bundle, the collector terminal includes a plate-like portion, the rectangular secondary battery further comprises a clamping portion that clamps, along with an edge-portion end surface of the plate-like portion, the tab bundle, each collector tab includes a flat portion that extends along an upper surface of the plate-like portion on a side of the cover plate in the height direction, and the flat portion includes the joint portion that is joined to the plate-like portion. an electrode body that includes a plurality of stacked electrode plates (20,30); a rectangular outer casing that has an opening and that accommodates the electrode body; a cover plate that seals the opening and that is provided with an external terminal (18,19) on a side opposite to a side of the electrode body; and a collector terminal that is electrically connected to the external terminal (18,19) and that is disposed inside the rectangular outer casing, wherein each electrode plate (20,30) includes an active material arrangement portion and a collector tab, the active material arrangement portion including a plate-like core body and an active material containing layer that is provided at the core body, the collector tab being integrated with the core body and protruding from the active material arrangement portion, wherein each collector tab includes a curved portion and an end (22b,22c), the curved portion being positioned between the active material arrangement portion corresponding thereto and the collector terminal in a height direction of the rectangular outer casing and having at least a part thereof curved, the end (22b,22c) being positioned at the curved portion on a side opposite to a side of the active material arrangement portion, and wherein each end (22b,22c) includes a joint portion that is joined and electrically connected to the collector terminal; characterized in that the collector tabs that are included in the plurality of electrode plates (20,30) are disposed so as to overlap each other and constitute a tab bundle, the collector terminal includes a plate-like portion, the rectangular secondary battery further comprises a clamping portion that clamps, along with an edge-portion end surface of the plate-like portion, the tab bundle, each collector tab includes a flat portion that extends along an upper surface of the plate-like portion on a side of the cover plate in the height direction, and the flat portion includes the joint portion that is joined to the plate-like portion.