An amplifier module that is disposed between a wireless communication antenna and a body unit of a wireless communication apparatus and that is connected to the antenna and the body unit through a wiring member (30A, 30B), the amplifier module comprising: an antenna-side terminal connected to the antenna; a body-side terminal connected to the body unit; an amplification circuit (121, 122, 123, 124, 125) disposed between the antenna-side terminal and the body-side terminal; an antenna detection circuit configured to detect electric characteristics of the antenna-side terminal; characterized by a characteristic variable circuit configured to change electric characteristics of the body-side terminal based on the electric characteristics of the antenna-side terminal detected by the antenna detection circuit, wherein the characteristic variable circuit includes a first switch element connected between the body-side terminal and a power source terminal of the amplification circuit (121, 122, 123, 124, 125), and a second switch element connected between the body-side terminal and the reference potential point, and a resistance portion for current restriction connected between the reference potential point and the second switch element, wherein when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state in which the antenna is normally connected to the antenna-side terminal, the first switch element is closed and the second switch element is opened, when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state in which the antenna is not connected to the antenna-side terminal, the first switch element and the second switch element are opened, and when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state of short-circuit between the antenna-side terminal and the reference potential point, the first switch element is opened and the second switch element is closed. an antenna-side terminal connected to the antenna; a body-side terminal connected to the body unit; an amplification circuit (121, 122, 123, 124, 125) disposed between the antenna-side terminal and the body-side terminal; an antenna detection circuit configured to detect electric characteristics of the antenna-side terminal; characterized by a characteristic variable circuit configured to change electric characteristics of the body-side terminal based on the electric characteristics of the antenna-side terminal detected by the antenna detection circuit, wherein the characteristic variable circuit includes a first switch element connected between the body-side terminal and a power source terminal of the amplification circuit (121, 122, 123, 124, 125), and a second switch element connected between the body-side terminal and the reference potential point, and a resistance portion for current restriction connected between the reference potential point and the second switch element, wherein a first switch element connected between the body-side terminal and a power source terminal of the amplification circuit (121, 122, 123, 124, 125), and a second switch element connected between the body-side terminal and the reference potential point, and a resistance portion for current restriction connected between the reference potential point and the second switch element, wherein when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state in which the antenna is normally connected to the antenna-side terminal, the first switch element is closed and the second switch element is opened, when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state in which the antenna is not connected to the antenna-side terminal, the first switch element and the second switch element are opened, and when the electric characteristics of the antenna-side terminal detected by the antenna detection circuit indicate the state of short-circuit between the antenna-side terminal and the reference potential point, the first switch element is opened and the second switch element is closed.