The sensor inserting device includes a device body, a movement mechanism which inserts a detector and an insertion needle into a body of a patient by moving a sensor with the insertion needle, and a dwelling member which is arranged on a moving path of the sensor and attached to the sensor by movement of the sensor caused by the movement mechanism. The dwelling member is allowed to dwell on the skin of the patient with the sensor and the transmitter connected at a location in which the detector is inserted into the body of the patient.
