A plasma chemical vapor deposition device comprising: a chamber configured to accommodate a workpiece inside the chamber, the chamber being configured to decompose a process gas by turning the process gas into plasma inside the chamber such that a film is deposited on the workpiece; a first conductor having an elongated shape, the first conductor being configured such that one end makes contact with the workpiece inside the chamber and the other end is placed outside the chamber; a second conductor having a tubular shape, the second conductor being placed coaxially with the first conductor such that the first conductor is placed inside the second conductor; a high-frequency output device connected to the first conductor and the second conductor, the high-frequency output device being configured to cause a microwave to flow through a surface of the first conductor; and a direct-current power supply configured to output a direct voltage to the first conductor, wherein: a first connecting portion of the first conductor with the high-frequency output device and a second connecting portion of the first conductor with the direct-current power supply are both placed outside the chamber; a distance from the one end of the first conductor to the first connecting portion is shorter than a distance from the one end of the first conductor to the second connecting portion; and an impedance change portion is provided between the first connecting portion and the second connecting portion in the first conductor, the impedance change portion having an impedance different from an impedance between the one end of the first conductor and the first connecting portion. a chamber configured to accommodate a workpiece inside the chamber, the chamber being configured to decompose a process gas by turning the process gas into plasma inside the chamber such that a film is deposited on the workpiece; a first conductor having an elongated shape, the first conductor being configured such that one end makes contact with the workpiece inside the chamber and the other end is placed outside the chamber; a second conductor having a tubular shape, the second conductor being placed coaxially with the first conductor such that the first conductor is placed inside the second conductor; a high-frequency output device connected to the first conductor and the second conductor, the high-frequency output device being configured to cause a microwave to flow through a surface of the first conductor; and a direct-current power supply configured to output a direct voltage to the first conductor, wherein: a first connecting portion of the first conductor with the high-frequency output device and a second connecting portion of the first conductor with the direct-current power supply are both placed outside the chamber; a distance from the one end of the first conductor to the first connecting portion is shorter than a distance from the one end of the first conductor to the second connecting portion; and an impedance change portion is provided between the first connecting portion and the second connecting portion in the first conductor, the impedance change portion having an impedance different from an impedance between the one end of the first conductor and the first connecting portion. a first connecting portion of the first conductor with the high-frequency output device and a second connecting portion of the first conductor with the direct-current power supply are both placed outside the chamber; a distance from the one end of the first conductor to the first connecting portion is shorter than a distance from the one end of the first conductor to the second connecting portion; and an impedance change portion is provided between the first connecting portion and the second connecting portion in the first conductor, the impedance change portion having an impedance different from an impedance between the one end of the first conductor and the first connecting portion.