A hydraulic transmission comprising: a hydraulic pump configured to pressurize working oil; a hydraulic motor configured to be driven by the working oil pressurized by the hydraulic pump; a high pressure line which connects an outlet side of the hydraulic pump and an inlet side of the hydraulic motor; a low pressure line which connects an outlet side of the hydraulic motor and an inlet side of the hydraulic pump; a reservoir tank for storing the working oil, the reservoir tank being connected to the low pressure line; and a boost pump for feeding the working oil stored in the reservoir tank to the low pressure line; a first branch line which is branched from the low pressure line and which is communicated with a bearing or a seal of at least one of the hydraulic pump or the hydraulic motor; and characterized in that the hydraulic transmission further comprises a shutoff valve disposed in the first branch line and configured to control supply of the working oil to the bearing or the seal from the low pressure line via the first branch line, and in that the hydraulic transmission is configured such that the working oil is not supplied from the low pressure line to the bearing or the seal of the at least one of the hydraulic pump or the hydraulic motor at least during abnormal stop of the boost pump, and the shutoff valve is configured to be in an open state during normal operation of the boost pump, and to be in a closed state during the abnormal stop of the boost pump so as to shut off the supply of the working oil to the bearing or the seal from the low pressure line via the first branch line. a hydraulic pump configured to pressurize working oil; a hydraulic motor configured to be driven by the working oil pressurized by the hydraulic pump; a high pressure line which connects an outlet side of the hydraulic pump and an inlet side of the hydraulic motor; a low pressure line which connects an outlet side of the hydraulic motor and an inlet side of the hydraulic pump; a reservoir tank for storing the working oil, the reservoir tank being connected to the low pressure line; and a boost pump for feeding the working oil stored in the reservoir tank to the low pressure line; a first branch line which is branched from the low pressure line and which is communicated with a bearing or a seal of at least one of the hydraulic pump or the hydraulic motor; and characterized in that the hydraulic transmission further comprises a shutoff valve disposed in the first branch line and configured to control supply of the working oil to the bearing or the seal from the low pressure line via the first branch line, and in that the hydraulic transmission is configured such that the working oil is not supplied from the low pressure line to the bearing or the seal of the at least one of the hydraulic pump or the hydraulic motor at least during abnormal stop of the boost pump, and the shutoff valve is configured to be in an open state during normal operation of the boost pump, and to be in a closed state during the abnormal stop of the boost pump so as to shut off the supply of the working oil to the bearing or the seal from the low pressure line via the first branch line.