PROBLEM TO BE SOLVED: To provide an anchor catheter with which anchor technique can be carried out more readily and safely carried out than the prior art without being provided with a balloon catheter on a side branch.SOLUTION: The anchor catheter 10 includes: a catheter insertion cylindrical body 20 with a catheter cavity 21 into which a treatment catheter can be replacebaly inserted; an expandable body 30 disposed on an outer periphery 22 of the catheter insertion cylindrical body 20; and a shaft 40 extending from a proximal end of the catheter insertion cylindrical body 20.