To provide a liquid ring vacuum pump device having a simple structure and requiring less cost.

This liquid ring vacuum pump device includes: a liquid ring vacuum pump 3; a replenishing water tank 5 replenishing seal water to the liquid ring vacuum pump 3 through a replenishing pipe 4; and a drainage/exhaust pipe 6 returning drainage and exhaust which are discharged from the liquid ring vacuum pump 3 to the replenishing water tank 5. The inside of the replenishing water tank 5 is divided into two spaces 52, 53 by a partition board 51. The capacity of one space 52 is formed sufficiently larger than the capacity of the other space 53, and the one space 52 communicates with the other space 53 through an upper portion. An opening 55 is formed in the portion of the constant height h of the partition board 51 forming the other space 53, and a drain port 56 is formed in the other space 53 so that a part of water in the other space 53 is discharged outside of the replenishing water tank 5. The end 6a of the drainage/exhaust pipe 6 is arranged in the other space 53, and a ball tap for replenishing cooling water is formed in the one space 52.