PURPOSE: To provide a variable air capacitor with an insulated shaft wherein assembly time is shortened, assembly accuracy and mechanical strength are improved.

CONSTITUTION: This variable air capacitor with an insulated shaft is provided with rotor vanes 1, a metal shaft 4, stators 5 and a metal case 6 similarly to an insulated shaft variable air capacitor of a prior technique. On the other hand, a rotor is provided with an insulated shaft 2 and a metal film 3 formed on the circular side of this shaft 2 by a metal evaporation technique or the like in place of the insulation shaft 2 and a rotor shaft.