An electronic apparatus is provided which, even when the electronic apparatus configuring a node is implanted in the body of an object animal, makes the object animal hard to feel stress and can acquire effective data about the natural behavior and state of the object animal. As shown in FIG. 12, a module unit and a battery are arranged separated from each other. That is, an electronic apparatus according to the present embodiment 1 adopts a case including a first capacity part and a second capacity part both arranged separated from each other to thereby accommodate the module unit in an internal space of the first capacity part and accommodate the battery in an internal space of the second capacity part.