To provide a catheter apparatus capable of performing removal of an embolus such as a thrombus, administration of a drug, etc. and sampling of body fluid such as blood at the same time inside a lumen of the human body, the catheter apparatus has a catheter 10 that is inserted into a lumen of the human body, a branch portion 40 which is connected to a base end portion 12 of the catheter 10 and is provided with an insertion hole to pass a guide wire used in inserting the catheter 10 in the lumen of the human body, and liquid introducing means 30 for introducing liquid such as a drug solution into the catheter 10 through a tube 34 connected to the branch portion 40, where at a front end 11 of the catheter 10 is disposed embolus trapping means 20 for trapping an embolus inside the lumen of the human body.
