A living body information acquiring apparatus according to the present invention includes: a living body information acquiring section for acquiring living body information in a living body a wireless transmission section for wirelessly transmitting the living body information to outside of the living body a power section for supplying driving power of the living body information acquiring section and the wireless transmission section a magnetic field detecting section for detecting a magnetic field from outside and outputting a detection result as an electric signal and a power supply control section for controlling a supply state of the driving power supplied from the power section to the living body information acquiring section and the wireless transmission section based on the electric signal.