A slurry application device comprising: a slurry supply unit configured to supply slurry to a surface of a traveling base material; a slurry application unit including a first roll body (31, 32) disposed at the downstream side in a travel direction of the base material in relation to the slurry supply unit and configured to press the first roll body against the slurry supplied to the surface of the base material to apply the slurry onto the surface of the base material and to adjust an adhesion amount of the slurry applied on and adhering to the surface of the base material such that a film thickness of the slurry of the surface of the base material becomes one time or more and two times or less of a target film thickness; and a slurry adhesion amount adjustment unit including a second roll body (41, 42) disposed at the downstream side in the travel direction of the base material in relation to the slurry application unit and configured to press the second roll body against the slurry applied on the surface of the base material to adjust the slurry adhesion amount such that the film thickness of the slurry on the surface of the base material becomes the target film thickness, characterized in that the second roll body (41, 42) is a groove attachment rubber roll whose outer circumferential surface is provided with a plurality of grooves arranged in a width direction of the base material and inclined with respect to the travel direction of the base material, and wherein the groove attachment rubber roll adjusts the slurry adhesion amount in such a manner that the outer circumferential surface provided with the plurality of grooves is pressed against the slurry of the surface of the base material. a slurry supply unit configured to supply slurry to a surface of a traveling base material; a slurry application unit including a first roll body (31, 32) disposed at the downstream side in a travel direction of the base material in relation to the slurry supply unit and configured to press the first roll body against the slurry supplied to the surface of the base material to apply the slurry onto the surface of the base material and to adjust an adhesion amount of the slurry applied on and adhering to the surface of the base material such that a film thickness of the slurry of the surface of the base material becomes one time or more and two times or less of a target film thickness; and a slurry adhesion amount adjustment unit including a second roll body (41, 42) disposed at the downstream side in the travel direction of the base material in relation to the slurry application unit and configured to press the second roll body against the slurry applied on the surface of the base material to adjust the slurry adhesion amount such that the film thickness of the slurry on the surface of the base material becomes the target film thickness, characterized in that the second roll body (41, 42) is a groove attachment rubber roll whose outer circumferential surface is provided with a plurality of grooves arranged in a width direction of the base material and inclined with respect to the travel direction of the base material, and wherein the groove attachment rubber roll adjusts the slurry adhesion amount in such a manner that the outer circumferential surface provided with the plurality of grooves is pressed against the slurry of the surface of the base material.