A vacuum pump is provided with which, even in the event of breakage of a rotor blade, broken pieces of the rotor blade are unlikely to scatter from an outlet port. A vacuum pump includes a rotor blade configured to rotate about a vertical axis and a casing housing the rotor blade, and is configured to exhaust sucked gas in a radial direction of the rotor blade by rotation of the rotor blade. An outlet port for the gas is provided at a position that is offset from a position of a gas exit portion of the rotor blade in a direction of the vertical axis.