It is an object of the invention to facilitate confirmation of detection results while allowing magnetic fluid detection operation to be carried out without interference from a cable.The solution is a magnetic fluid detecting device 1 that detects magnetic fluid that has been injected into a living body, the device comprising a detector 2 that detects magnetic fluid in the body when it is in contact with or adjacent to the body, an output device 3 that outputs the detection results in a prescribed output form, a controller 4 that controls the output device 3 based on the detected value inputted from the detector 2, and a power supply module 5 that supplies power to the detector 2, output device 3 and controller 4, using a battery B as the power source, the detector 2, output device 3, controller 4 and power supply module 5 being integrated so as to allow holding with one hand.
