A body-insertable apparatus that is used in a state of being introduced in a body of a subject, and that performs a predetermined function inside the body of the subject includes an imaging circuit 27, a battery 40 that supplies with energy to be used to drive the imaging circuit 27, a power switch 33 that switches energy supply to the imaging circuit 27 from the battery 40, a switch control circuit 32 that performs a switching control of the power switch 33, and a signal detecting circuit 31 that detects a magnet and that transmits, to the switch control circuit, a control signal to cause the power switch 33 to toggle the switching control based on this detection state, and is possible to be turned on and off a main switch at a desirable timing before introduction into the body of the subject, thereby achieving energy saving in which a life of a battery is saved, and suppressing unnecessary radio wave radiation.