A new element, named "standard conductance element (SCE)", has been developed for in situ calibration of ionization gauges and quadrupole mass spectrometers. The SCE is a stainless-steel sintered filter with a pore size of less than 1 μm. Since the gas flow through the SCE satisfies the molecular flow condition even at the pressure up to 10⁴ Pa, several useful characteristics of molecular flow are available: (1) calibration for various gas species only with this single leak element, (2) easy multi-point calibration, (3) calibration for mixture gases, (4) small and theoretical temperature dependence of flow rate. These advantages were experimentally demonstrated. The SCE is supplied to users with a calibration certificate describing its molecular conductance. Users can introduce arbitrary test gases with the known flow rate to their vacuum chamber through the SCE in their laboratories.