A method for producing a battery, the battery comprising: a battery case made of metal, including a liquid inlet; an electrode body accommodated in the battery case, the electrode body including an electrode opposed part in which a positive active material layer of a positive electrode sheet and a negative active material layer of a negative electrode sheet are opposed to each other; and an electrolytic solution contained in the battery case, characterized in that the method comprises injecting (S2, S12) the electrolytic solution into the battery case through the liquid inlet, the injecting (S2, S12) includes: a first liquid-injecting step of injecting the electrolytic solution of a predetermined first injection amount while air pressure in the battery case is regulated to a predetermined first air pressure, the predetermined first injection amount being determined so that a liquid-level height of the injected electrolytic solution falls within an intermediate liquid-level range (AHc) (Ha≤H<Hb) in which the liquid-level height of the injected electrolytic solution is equal to or higher than a first reference height (Ha) at which the whole electrode opposed part of the electrode body is immersed in the electrolytic solution but is lower than a second reference height (Hb) at which the electrolytic solution reaches the liquid inlet; and a second liquid-injecting step (S22, S122) of injecting the electrolytic solution of a second injection amount (V2=V-V1) that is a remaining amount up to a specified amount while increasing the air pressure in the battery case to a second air pressure (P2 > P1) higher than the first air pressure and maintaining the liquid-level height of the electrolytic solution within the intermediate liquid-level range (AHc). a battery case made of metal, including a liquid inlet; an electrode body accommodated in the battery case, the electrode body including an electrode opposed part in which a positive active material layer of a positive electrode sheet and a negative active material layer of a negative electrode sheet are opposed to each other; and an electrolytic solution contained in the battery case, characterized in that the method comprises injecting (S2, S12) the electrolytic solution into the battery case through the liquid inlet, the injecting (S2, S12) includes: a first liquid-injecting step of injecting the electrolytic solution of a predetermined first injection amount while air pressure in the battery case is regulated to a predetermined first air pressure, the predetermined first injection amount being determined so that a liquid-level height of the injected electrolytic solution falls within an intermediate liquid-level range (AHc) (Ha≤H<Hb) in which the liquid-level height of the injected electrolytic solution is equal to or higher than a first reference height (Ha) at which the whole electrode opposed part of the electrode body is immersed in the electrolytic solution but is lower than a second reference height (Hb) at which the electrolytic solution reaches the liquid inlet; and a second liquid-injecting step (S22, S122) of injecting the electrolytic solution of a second injection amount (V2=V-V1) that is a remaining amount up to a specified amount while increasing the air pressure in the battery case to a second air pressure (P2 > P1) higher than the first air pressure and maintaining the liquid-level height of the electrolytic solution within the intermediate liquid-level range (AHc). a first liquid-injecting step of injecting the electrolytic solution of a predetermined first injection amount while air pressure in the battery case is regulated to a predetermined first air pressure, the predetermined first injection amount being determined so that a liquid-level height of the injected electrolytic solution falls within an intermediate liquid-level range (AHc) (Ha≤H<Hb) in which the liquid-level height of the injected electrolytic solution is equal to or higher than a first reference height (Ha) at which the whole electrode opposed part of the electrode body is immersed in the electrolytic solution but is lower than a second reference height (Hb) at which the electrolytic solution reaches the liquid inlet; and a second liquid-injecting step (S22, S122) of injecting the electrolytic solution of a second injection amount (V2=V-V1) that is a remaining amount up to a specified amount while increasing the air pressure in the battery case to a second air pressure (P2 > P1) higher than the first air pressure and maintaining the liquid-level height of the electrolytic solution within the intermediate liquid-level range (AHc).