An amplifier circuit includes a first amplifier having an input and an output, and a second amplifier having an input that communicates with the output of the first amplifier, and an output. The transmission apparatus comprising a monitoring unit, a symbol-specifying unit, a signal point moving unit, and a transmission unit. The first pipe has a sliding portion that has an arc-shaped cross section and that slides along the inner surface of the body case, and this sliding portion is arranged inside the body case, which is substantially rectangular, as seen in a plan view.