To stably and properly monitor an inside of a body by using an easily operable placement technique, a capsule endoscope 101 to be swallowed from an oral cavity 200 to acquire in-vivo information of a subject 201 and to wirelessly output for a transmission of the in-vivo information to an outside of a body, a string member 103 that is connected to the capsule endoscope 101 for positioning the capsule endoscope 101 at a gastric cardia 202, and a fixing portion 104 that is a portion of the string member 103, is provided on a position with which a length from the capsule endoscope 101 corresponds to a length from the gastric cardia 202 to the inside of an esophageal region 203 for fixing the string member 103 that has located the capsule endoscope 101 at the gastric cardia 202 to the inside of the esophageal region 203 by an endoscopic fixture are included. As a result, the capsule endoscope 101 is placed at a position of the gastric cardia 202 where an entire inside of the stomach is easily inspected, and the capsule endoscope 101 itself can easily be placed inside the esophageal region by using the fixing portion 104.
