A phase shifter, comprising a cavity, a metal strip, a sliding dielectric, a fastener, a signal input terminal, and a signal output terminal, wherein the metal strip is connected to the signal input terminal and the signal output terminal, the metal strip comprises a transmission portion and a fastening portion connected to the transmission portion; the fastener is connected to the fastening portion to fasten the metal strip in the cavity, and the transmission portion is suspended in the cavity; the sliding dielectric is disposed in the cavity and movable relative to the transmission portion of the metal strip; the fastener comprises a first fastener and a second fastener, the metal strip comprises a first surface and a second surface opposite to the first surface, and the first fastener comprises a first part disposed on the first surface and a second part disposed on the second surface; and both ends that are of the first part of the first fastener and the second part of the first fastener and that are far away from the metal strip abut against an inner wall of the cavity; the second fastener is located on the same side as the first fastener and is spaced away from the first fastener; and the second fastener comprises a first part disposed on the first surface of the metal strip and a second part disposed on the second surface, and both ends that are of the first part of the second fastener and the second part of the second fastener and that are far away from the metal strip abut against an inner wall of the cavity; the second fastener is provided with an opening, which runs through the first part of the second fastener and the second part of the second fastener, a side wall of the cavity is provided with a through hole corresponding to the opening, and a limiting component passes through the through hole and the opening, the sliding dielectric is flat, and the sliding dielectric is located on one side of the first surface or the second surface of the metal strip, or one sliding dielectric is located on one side of the first surface of the metal strip and one sliding dielectric is located on one side of the second surface of the metal strip, characterized in that a conduit is provided on the sliding dielectric, the second fastener is inserted into the conduit and movable along the conduit, and an extension direction of the conduit is the same as that of the metal strip. the metal strip is connected to the signal input terminal and the signal output terminal, the metal strip comprises a transmission portion and a fastening portion connected to the transmission portion; the fastener is connected to the fastening portion to fasten the metal strip in the cavity, and the transmission portion is suspended in the cavity; the sliding dielectric is disposed in the cavity and movable relative to the transmission portion of the metal strip; the fastener comprises a first fastener and a second fastener, the metal strip comprises a first surface and a second surface opposite to the first surface, and the first fastener comprises a first part disposed on the first surface and a second part disposed on the second surface; and both ends that are of the first part of the first fastener and the second part of the first fastener and that are far away from the metal strip abut against an inner wall of the cavity; the second fastener is located on the same side as the first fastener and is spaced away from the first fastener; and the second fastener comprises a first part disposed on the first surface of the metal strip and a second part disposed on the second surface, and both ends that are of the first part of the second fastener and the second part of the second fastener and that are far away from the metal strip abut against an inner wall of the cavity; the second fastener is provided with an opening, which runs through the first part of the second fastener and the second part of the second fastener, a side wall of the cavity is provided with a through hole corresponding to the opening, and a limiting component passes through the through hole and the opening, the sliding dielectric is flat, and the sliding dielectric is located on one side of the first surface or the second surface of the metal strip, or one sliding dielectric is located on one side of the first surface of the metal strip and one sliding dielectric is located on one side of the second surface of the metal strip, characterized in that a conduit is provided on the sliding dielectric, the second fastener is inserted into the conduit and movable along the conduit, and an extension direction of the conduit is the same as that of the metal strip.