A vacuum pump comprises a stator disk that is used in a first gas transfer mechanism for transferring gas from an inlet port side to an outlet port side and forming a spiral groove exhaust portion by interaction with a rotating disk, wherein spiral grooves, each spiral groove including a root portion and a ridge portion, are formed in at least a part of opposed surfaces of the stator disk and the rotating disk, wherein a plurality of connection holes is provided in the stator disk, and characterized in that: the plurality of connection holes comprise a plurality of opening portions, penetrating from the inlet port side to the outlet port side and opening only in the root portions in an inner diameter side of the stator disk, wherein the plurality of opening portions are provided in an inner circumference side portion of the stator disk, wherein each opening portion connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side, or the plurality of connection holes comprise a plurality of through-holes, penetrating from the inlet port side to the outlet port side and formed only in the root portions of the stator disk, wherein the plurality of through-holes are provided in the inner circumference side portion of the stator disk, wherein each through-hole connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side. spiral grooves, each spiral groove including a root portion and a ridge portion, are formed in at least a part of opposed surfaces of the stator disk and the rotating disk, wherein a plurality of connection holes is provided in the stator disk, and characterized in that: the plurality of connection holes comprise a plurality of opening portions, penetrating from the inlet port side to the outlet port side and opening only in the root portions in an inner diameter side of the stator disk, wherein the plurality of opening portions are provided in an inner circumference side portion of the stator disk, wherein each opening portion connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side, or the plurality of connection holes comprise a plurality of through-holes, penetrating from the inlet port side to the outlet port side and formed only in the root portions of the stator disk, wherein the plurality of through-holes are provided in the inner circumference side portion of the stator disk, wherein each through-hole connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side. the plurality of connection holes comprise a plurality of opening portions, penetrating from the inlet port side to the outlet port side and opening only in the root portions in an inner diameter side of the stator disk, wherein the plurality of opening portions are provided in an inner circumference side portion of the stator disk, wherein each opening portion connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side, or the plurality of connection holes comprise a plurality of through-holes, penetrating from the inlet port side to the outlet port side and formed only in the root portions of the stator disk, wherein the plurality of through-holes are provided in the inner circumference side portion of the stator disk, wherein each through-hole connects, among the root portions, the root portion formed on a surface of the stator disk on the inlet port side with the root portion formed on a surface of the stator disk on the outlet port side.