A power supply system including a combination of a cogeneration device and a power supply other than a grid power source, the power supply system comprising: a distribution board comprising a main breaker that is connected between a grid power source and a first load; a power conversion apparatus connected with the power supply, and comprising an interconnection terminal and an autonomous terminal, the interconnection terminal being for supplying electric power to the main breaker for a period during which grid power is supplied from the grid power source, and the autonomous terminal being for extracting the electric power from the power conversion apparatus for a period during which supplying of the grid power from the grid power source is stopped; an autonomous distribution board configured to receive feeding of power via the distribution board for the period during which the grid power is supplied from the grid power source, while receiving the electric power via the autonomous terminal of the power conversion apparatus for the period during which supplying of the grid power from the grid power source is stopped, the autonomous distribution board being connected with a second load; the cogeneration device connected with the autonomous distribution board, and configured to perform generating of electricity and heating of water, the electricity generated by the cogeneration device being prohibited to be made reversely flow into the grid power source; and a measurement point switching apparatus configured to switch between a first current sensor and a second current sensor to set specific electric power to be output by the cogeneration device, the first current sensor being configured to monitor a current that flows through the main breaker, the second current sensor being configured to monitor a current that is supplied from the power conversion apparatus to the autonomous distribution board, the measurement point switching apparatus being configured to select the first current sensor for the period during which the grid power is supplied from the grid power source, and select the second current sensor for the period during which supplying of the grid power from the grid power source is stopped, and the cogeneration device being configured to adjust an output thereof based on an output of either the first current sensor or the second current sensor selected by the measurement point switching apparatus so that the specific electric power output by the cogeneration device is consumed by the first and second loads (60, 61). a distribution board comprising a main breaker that is connected between a grid power source and a first load; a power conversion apparatus connected with the power supply, and comprising an interconnection terminal and an autonomous terminal, the interconnection terminal being for supplying electric power to the main breaker for a period during which grid power is supplied from the grid power source, and the autonomous terminal being for extracting the electric power from the power conversion apparatus for a period during which supplying of the grid power from the grid power source is stopped; an autonomous distribution board configured to receive feeding of power via the distribution board for the period during which the grid power is supplied from the grid power source, while receiving the electric power via the autonomous terminal of the power conversion apparatus for the period during which supplying of the grid power from the grid power source is stopped, the autonomous distribution board being connected with a second load; the cogeneration device connected with the autonomous distribution board, and configured to perform generating of electricity and heating of water, the electricity generated by the cogeneration device being prohibited to be made reversely flow into the grid power source; and a measurement point switching apparatus configured to switch between a first current sensor and a second current sensor to set specific electric power to be output by the cogeneration device, the first current sensor being configured to monitor a current that flows through the main breaker, the second current sensor being configured to monitor a current that is supplied from the power conversion apparatus to the autonomous distribution board, the measurement point switching apparatus being configured to select the first current sensor for the period during which the grid power is supplied from the grid power source, and select the second current sensor for the period during which supplying of the grid power from the grid power source is stopped, and the cogeneration device being configured to adjust an output thereof based on an output of either the first current sensor or the second current sensor selected by the measurement point switching apparatus so that the specific electric power output by the cogeneration device is consumed by the first and second loads (60, 61).