A capsule endoscope includes: a function-performing device configured to perform a function a power source configured to supply power a first inductor including a cored coil, the first inductor being configured to boost a voltage of the power and output a first voltage a second inductor including an air-cored coil, the second inductor being configured to boost a voltage of the power and output a second voltage a detector configured to detect a magnetic field applied from outside and a controller configured to perform control to supply first power according to the first voltage to the function-performing device, when the magnetic field detected by the detector has a magnitude less than a threshold, and to supply second power according to the second voltage to the function-performing device, when the magnetic field detected by the detector has a magnitude not less than a threshold.
