A sensor applicator assembly for a continuous glucose monitoring system, comprising: - a sensor module configured to be attachable to a human body for periodically measuring a blood glucose level and to allow a separate transmitter to be connected thereto to transmit a glucose measurement result to an external device; and - an applicator allowing the sensor module to be coupled and fixed to an inner portion thereof, and being operable to eject the sensor module in response to a user's manipulation, - wherein the applicator and the sensor module are fitted together as a single unitary product, with the sensor module being preinstalled in the applicator , such that the applicator is operable by the user's manipulation to eject the sensor module so that the sensor module is attached to the human body, - wherein the applicator is configured to have one open side, - wherein a separate protective cap is detachably coupled to the open side of the applicator to block the sensor module , preinstalled in the applicator , from being exposed externally, - wherein the protective cap is provided with a locking member to prevent the protective cap , coupled to the applicator , from being detached from the applicator , - wherein the applicator is provided with a locking catch recess , and - the locking member includes: - a locking lever pivotably coupled to one side of the protective cap ; and - a locking catch protrusion provided on one end of the locking lever , and - wherein the locking lever is elastically supported in a direction in which the locking catch protrusion is fitted into and engaged with the locking catch recesses . - a sensor module configured to be attachable to a human body for periodically measuring a blood glucose level and to allow a separate transmitter to be connected thereto to transmit a glucose measurement result to an external device; and - an applicator allowing the sensor module to be coupled and fixed to an inner portion thereof, and being operable to eject the sensor module in response to a user's manipulation, - wherein the applicator and the sensor module are fitted together as a single unitary product, with the sensor module being preinstalled in the applicator , such that the applicator is operable by the user's manipulation to eject the sensor module so that the sensor module is attached to the human body, - wherein the applicator is configured to have one open side, - wherein a separate protective cap is detachably coupled to the open side of the applicator to block the sensor module , preinstalled in the applicator , from being exposed externally, - wherein the protective cap is provided with a locking member to prevent the protective cap , coupled to the applicator , from being detached from the applicator , - wherein the applicator is provided with a locking catch recess , and - the locking member includes: - a locking lever pivotably coupled to one side of the protective cap ; and - a locking catch protrusion provided on one end of the locking lever , and - wherein the locking lever is elastically supported in a direction in which the locking catch protrusion is fitted into and engaged with the locking catch recesses . - a locking lever pivotably coupled to one side of the protective cap ; and - a locking catch protrusion provided on one end of the locking lever , and - wherein the locking lever is elastically supported in a direction in which the locking catch protrusion is fitted into and engaged with the locking catch recesses . <EOS>