The present invention relates to a composite catheter and, more specifically, to a composite catheter wherein respective catheters used for various treatment actions, such as procedures, operations, drug injections, and high-frequency treatments, are integrated into a single usable device. In order to accomplish the above purpose, a composite catheter according to the present invention comprises: a housing comprising a hollow portion formed to penetrate same in the longitudinal direction, a first mounting portion connected to the front end portion of the hollow portion, a second mounting portion connected to the rear end portion of the hollow portion, and a third mounting portion formed along one side of the second mounting portion； a guide having a fitting hole formed to penetrate same in the longitudinal direction, a part of the front end of the guide being coupled to the first mounting portion so as to be exposed to the front end of the housing； an inner body having an introduction hole formed to penetrate same in the longitudinal direction, a first introduction port for a medical device, which is connected to the rear end portion of the introduction hole, and a second introduction port for a drug, which branches off toward the other side of the introduction hole to be connected thereto, the inner body being mounted on the second mounting portion such that the first introduction port and the second introduction port are exposed to the outside of the housing； a connector mounted on the third mounting portion to be exposed to the outside of the housing； a tube made of a flexible material so as to exhibit an elastic restoration force in parallel with the longitudinal direction, the tube having an insertion hole formed to penetrate same in the longitudinal direction and an electrode portion provided on the end portion of the front end thereof and electrically connected to the connector, the tube being fitted into the fitting hole such that, while the electrode portio
