Abstract: Provided is a body temperature sensor module to be attached to the skin including: a power supply unit electrically connected to a flexible printed circuit board and providing driving power; a temperature sensor mounted on one surface of the flexible printed circuit board and measuring the body temperature of the wearer; a communication module for transmitting information measured by the temperature sensor to an external communication module; a control unit for controlling the driving of the power supply unit, the temperature sensor and the communication module; a protection member for preventing the exposure of the flexible printed circuit board, the power supply unit, the temperature sensor, the communication module and the control unit to the outside; and a membrane layer separably attached to one surface of the protection member, and formed from a nanofiber web having micropores to be able to block moisture and allow the passage of air.