A charging device for a physiological signal transmitter is disclosed, wherein the physiological signal transmitter is to receive and externally transmit a physiological signal from a subcutaneous tissue of a living body, and has a first electrical connecting port. The charging device comprises a transmitter placing seat, a charging module and a locking module. The transmitter placing seat includes a bearing surface, and a first opening. The bearing surface disposes thereon the physiological signal transmitter; and the first opening aligns therewith the first electrical connecting port of the physiological signal transmitter. The charging module includes a second electrical connecting port, a third electrical connecting port and a circuit assembly. The second electrical connecting port is disposed in the first opening and moveable between a first position and a second position. The third electrical connecting port is for connecting thereto a power source. The circuit assembly is for performing charging and charging control on the physiological signal transmitter, and the circuit assembly is electrically connected to the second electrical connecting port and the third electrical connecting port. The locking module is extendable or retractable on the bearing surface for releasably positioning the physiological signal transmitter, wherein the charging module is driven to move the second electrical connecting port from the first position to the second position to be electrically connected to the first electrical connecting port, and the locking module is driven to protrude out of the bearing surface to fix the transmitter.