A living-body observation system is provided with: an in-vivo observation apparatus including: an in-vivo information acquiring section; a power source section; a magnetic field detection section that detects a magnetic field from outside and outputs a detected result as an electric signal; and a power supply section that controls a supply state of driving power supplied to the in-vivo information acquiring section, and the operation of the in-vivo information acquiring section, based on the electric signal; and a magnetic field generating section that is disposed outside the in-vivo observation apparatus and generates the magnetic field, wherein the power supply section includes a control section that controls the operation of the in-vivo information acquiring section of the in-vivo observation apparatus.