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.