A redox flow battery comprising: a positive electrolyte tank container which houses a positive electrolyte tank for storing a positive electrolyte; a negative electrolyte tank container which houses a negative electrolyte tank for storing a negative electrolyte; and a battery container which houses a battery cell including a positive electrode, a negative electrode, and a membrane, a positive electrolyte circulation mechanism configured to supply and circulate the positive electrolyte to the battery cell, and a negative electrolyte circulation mechanism configured to supply and circulate the negative electrolyte to the battery cell, wherein the battery container is placed on the roof of at least one of the positive electrolyte tank container and the negative electrolyte tank container, characterized in that: the battery container extends over and between the positive electrolyte tank container and the negative electrolyte tank container and is placed evenly on the roofs of the positive electrolyte tank container and the negative electrolyte tank container, when the redox flow battery is viewed from the top, the overlapping area between the battery container and the positive electrolyte tank container is substantially the same as the overlapping area between the battery container and the negative electrolyte tank container, the positive electrolyte tank container and the negative electrolyte tank container are arranged in parallel with a distance therebetween such that the longitudinal directions thereof are parallel to each other, the battery container is placed such that the longitudinal direction thereof is orthogonal to the longitudinal directions of the positive electrolyte tank container and the negative electrolyte tank container, and the placing positions of the battery container are the centers in the longitudinal direction of the positive electrolyte tank container and the negative electrolyte tank container, and reinforcing pillars are provided at positions overlapping with corners of the battery container in the positive electrolyte tank container and the negative electrolyte tank container. a positive electrolyte tank container which houses a positive electrolyte tank for storing a positive electrolyte; a negative electrolyte tank container which houses a negative electrolyte tank for storing a negative electrolyte; and a battery container which houses a battery cell including a positive electrode, a negative electrode, and a membrane, a positive electrolyte circulation mechanism configured to supply and circulate the positive electrolyte to the battery cell, and a negative electrolyte circulation mechanism configured to supply and circulate the negative electrolyte to the battery cell, wherein the battery container is placed on the roof of at least one of the positive electrolyte tank container and the negative electrolyte tank container, characterized in that: the battery container extends over and between the positive electrolyte tank container and the negative electrolyte tank container and is placed evenly on the roofs of the positive electrolyte tank container and the negative electrolyte tank container, when the redox flow battery is viewed from the top, the overlapping area between the battery container and the positive electrolyte tank container is substantially the same as the overlapping area between the battery container and the negative electrolyte tank container, the positive electrolyte tank container and the negative electrolyte tank container are arranged in parallel with a distance therebetween such that the longitudinal directions thereof are parallel to each other, the battery container is placed such that the longitudinal direction thereof is orthogonal to the longitudinal directions of the positive electrolyte tank container and the negative electrolyte tank container, and the placing positions of the battery container are the centers in the longitudinal direction of the positive electrolyte tank container and the negative electrolyte tank container, and reinforcing pillars are provided at positions overlapping with corners of the battery container in the positive electrolyte tank container and the negative electrolyte tank container. the battery container extends over and between the positive electrolyte tank container and the negative electrolyte tank container and is placed evenly on the roofs of the positive electrolyte tank container and the negative electrolyte tank container, when the redox flow battery is viewed from the top, the overlapping area between the battery container and the positive electrolyte tank container is substantially the same as the overlapping area between the battery container and the negative electrolyte tank container, the positive electrolyte tank container and the negative electrolyte tank container are arranged in parallel with a distance therebetween such that the longitudinal directions thereof are parallel to each other, the battery container is placed such that the longitudinal direction thereof is orthogonal to the longitudinal directions of the positive electrolyte tank container and the negative electrolyte tank container, and the placing positions of the battery container are the centers in the longitudinal direction of the positive electrolyte tank container and the negative electrolyte tank container, and reinforcing pillars are provided at positions overlapping with corners of the battery container in the positive electrolyte tank container and the negative electrolyte tank container.