The depth of insertion when inserting a urinary catheter in men is about 17-22 cm. The length of the urethra in men is this length. When a catheter is inserted, if it reaches about 17-22cm, in the majority of cases the urethra is located within the bladder. However, the clinical judgment is not based on the length, but on whether urine is drained out of the urethra. If urine is seen to drain out, then it is confirmed that the ureter has entered the bladder. However, if urine is not seen to drain out even if the insertion depth reaches about 17-22 cm, it is still not certain that the urethral tube is inserted into the bladder, and it is necessary to continue pushing inward until urine is seen to drain out. Also after urine is seen, it is recommended to insert about 3-4cm deeper and then to pump up the bladder of the urethra, so that there is no possibility of the bladder damaging the urethra.