A thread groove pump portion, which is an exhaust element, is structured such that a Siegbahn structure is attached onto a cylindrical thread, and such that respective parts are connected to each other at this attachment section. A flow channel of the Siegbahn portion and a flow channel of the cylindrical thread (the thread groove pump portion) are connected to each other so as to substantially form a right angle when viewed from an axis direction of the vacuum pump, thus, the flow channel of the Siegbahn portion and the flow channel of the thread groove pump portion are connected to each other. the length of a compression flow channel of the thread groove pump portion can be increased in a radial direction due to the connected Siegbahn portion.