A powder supply device for a secondary battery, including a case having a storing portion which is a gap for storing powder which is a material to be supplied and a rectangular opening communicating with the storing portion, the opening being formed on a lower end portion of the case, which is configured so that the powder is discharged from the opening, and is supplied to a member to which the powder is to be supplied and which is moved horizontally in an area vertically below the opening while being fallen from the opening, the powder supply device comprising: a rotor which makes the powder fall into the opening and is formed of a roller member having a circular column; and a mesh body which covers a lower end of the opening and allows the powder in the opening to pass therethrough; wherein a plurality of uneven portions or a plurality of projecting portions are formed on an outer circumferential portion of the rotor parallel to an axial direction of the rotor and at equal intervals in a circumferential direction, wherein the rotor is rotatably supported in the storing portion so that an axis of the rotor is parallel to a width direction of the opening as viewed in a plan view and is arranged horizontally, wherein a bottom portion of the storing portion is formed in an arc which is concentric with the outer circumferential portion of the rotor, wherein a gap which constitutes a conveyance passage for the powder is formed between the outer circumferential portion of the rotor and the bottom portion of the storing portion so that a distance between the outer circumferential portion and the bottom portion becomes a fixed value, and wherein the mesh body is arranged at a fixed distance from the outer circumferential portion of the rotor, characterized in that the powder supply device further comprises: a leveling mechanism including a pair of slide rails and a leveling plate which horizontally levels an upper surface of the powder supplied into the storing portion and stacked on an upper portion of the rotor. a rotor which makes the powder fall into the opening and is formed of a roller member having a circular column; and a mesh body which covers a lower end of the opening and allows the powder in the opening to pass therethrough; wherein a plurality of uneven portions or a plurality of projecting portions are formed on an outer circumferential portion of the rotor parallel to an axial direction of the rotor and at equal intervals in a circumferential direction, wherein the rotor is rotatably supported in the storing portion so that an axis of the rotor is parallel to a width direction of the opening as viewed in a plan view and is arranged horizontally, wherein a bottom portion of the storing portion is formed in an arc which is concentric with the outer circumferential portion of the rotor, wherein a gap which constitutes a conveyance passage for the powder is formed between the outer circumferential portion of the rotor and the bottom portion of the storing portion so that a distance between the outer circumferential portion and the bottom portion becomes a fixed value, and wherein the mesh body is arranged at a fixed distance from the outer circumferential portion of the rotor, characterized in that the powder supply device further comprises: a leveling mechanism including a pair of slide rails and a leveling plate which horizontally levels an upper surface of the powder supplied into the storing portion and stacked on an upper portion of the rotor.