The present invention relates to a sensor insertion device and a sensor insertion method. A sensor insertion device (10) includes a movement mechanism (16) which inserts a detection element (76) and an insertion needle (46) into the body of a subject. A grip member (86) of the movement mechanism (16) is blocked by a displacement preventing member (106) which prevents the grip member (86) from being displaced toward the body of the subject. When a data process unit (12) (e. g. , a transmitter) is attached to a device body (14), the displacement preventing member (106) is pushed by the data process unit (12) to turn. As a result, the blockage with respect to the grip member (86) is released.
