A polarization multiplexing optical receiving device (10, 100) comprising: a semiconductor optical element (20, 20C) for adjusting optical signal intensity of each of a TE mode and a TM mode of a polarization-multiplexed optical signal; a polarization beam splitter (30, 300) for separating the polarization-multiplexed optical signal into the TE mode optical signal and the TM mode optical signal; and a control circuit for calculating the optical signal intensity ratio between the TE mode optical signal and the TM mode optical signal, which have had the optical signal intensity thereof adjusted by the semiconductor optical element and which have been separated by the polarization beam splitter (30, 300), and for performing feedback control of the semiconductor optical element so that the calculated optical intensity ratio reaches a desired value, wherein the control circuit is configured to perform the feedback control of the semiconductor optical element by calculating applied current for adjusting the optical intensity ratio to a desired value and outputting it to the semiconductor optical element, wherein the semiconductor optical element is a semiconductor optical amplifier comprising: a first semiconductor amplifying portion having a gain of TE mode more dominant than a gain of TM mode; a second semiconductor amplifying portion having a gain of TM mode more dominant than a gain of TE mode; a first upper electrode for supplying a first current to the first semiconductor amplifying portion based on the applied current; a second upper electrode for supplying a second current to the second semiconductor amplifying portion based on the applied current; and a lower electrode which is a common electrode for the first semiconductor amplifying portion and the second semiconductor amplifying portion, and wherein the semiconductor optical element is arranged in a former stage of the polarization beam splitter (30, 300). a semiconductor optical element (20, 20C) for adjusting optical signal intensity of each of a TE mode and a TM mode of a polarization-multiplexed optical signal; a polarization beam splitter (30, 300) for separating the polarization-multiplexed optical signal into the TE mode optical signal and the TM mode optical signal; and a control circuit for calculating the optical signal intensity ratio between the TE mode optical signal and the TM mode optical signal, which have had the optical signal intensity thereof adjusted by the semiconductor optical element and which have been separated by the polarization beam splitter (30, 300), and for performing feedback control of the semiconductor optical element so that the calculated optical intensity ratio reaches a desired value, wherein the control circuit is configured to perform the feedback control of the semiconductor optical element by calculating applied current for adjusting the optical intensity ratio to a desired value and outputting it to the semiconductor optical element, wherein the semiconductor optical element is a semiconductor optical amplifier comprising: a first semiconductor amplifying portion having a gain of TE mode more dominant than a gain of TM mode; a second semiconductor amplifying portion having a gain of TM mode more dominant than a gain of TE mode; a first upper electrode for supplying a first current to the first semiconductor amplifying portion based on the applied current; a second upper electrode for supplying a second current to the second semiconductor amplifying portion based on the applied current; and a lower electrode which is a common electrode for the first semiconductor amplifying portion and the second semiconductor amplifying portion, and a first semiconductor amplifying portion having a gain of TE mode more dominant than a gain of TM mode; a second semiconductor amplifying portion having a gain of TM mode more dominant than a gain of TE mode; a first upper electrode for supplying a first current to the first semiconductor amplifying portion based on the applied current; a second upper electrode for supplying a second current to the second semiconductor amplifying portion based on the applied current; and a lower electrode which is a common electrode for the first semiconductor amplifying portion and the second semiconductor amplifying portion, and wherein the semiconductor optical element is arranged in a former stage of the polarization beam splitter (30, 300).