Disclosed is a catheter guide structure. The present invention comprises: a first guide module provided with an oxygen supply port a second guide module installed so as to be connected to the first guide module and provided with an inner space, which is opened only when catheter entry into the first guide module is required and a third guide module installed so as to be connected to the second guide module, for guiding entry of the catheter into the inside of the first guide module. According to the present invention, work efficiency can be secured when inserting the catheter for aspirating foreign substances such as phlegm, present in the respiratory system of a patient wearing an oxygen respirator, into the respirator on the patient, and when removing the catheter, thereby enabling rapid and efficient nursing treatment for the patient. Also, according to the present invention, cleaning and sterilizing work from the inside and the outside of the catheter provided on a medical suction device is made convenient.
