To provide a pump which can control the occurrence of a whistle noise in a suction passage.

When a crank bench 4 is rotated by the drive of a motor 3, each diaphragm part 14 is oscillated up and down one by one, and each pump chamber 21 is expanded and contracted one by one. When the pump chamber 21 is expanded, the air is sucked into the pump chamber 21 passing through the suction passage 31 and an intake hole 20. When the expanded pump chamber 21 is contracted, the air is discharged to the outside passing through a discharge passage 28 from a discharge hole 19. A concavity 31 shaped like a groove is provided at one part of the end edge of the opening of the suction passage 30.