A direction changing device (200; 200a; 200b; 200c; 300; 400; 500) for use with a flexible tubular medical device (22, 28) having a hub, the direction changing device (200; 200a; 200b; 200c; 300; 400; 500) comprising a direction changing section comprising: a first mounting section (58; 88; 242) that generally extends in first axial direction and being configured to allow a first portion of the tubular medical device (22, 28) to be received therein; a second mounting section (62; 90; 208; 244; 306; 406; 512) that generally extends in a second axial direction and being configured to allow a second portion of the tubular medical device (22, 28) to be received therein, the first and second mounting sections being fixed in spaced relation to each other with the first and second axial directions intersecting each other or being parallel to each other in plan view, so that with the first and second portions of the tubular medical device (22, 28) received therein, the first and second portions of the tubular medical device (22, 28) will extend in either transverse or parallel directions to each other; and an intermediate section (60, 27, 404) guiding the tubular medical device (22, 28) from the first mounting section (58; 88; 242) to the second mounting section (62; 90; 208; 244; 306; 406; 512); characterized by a tapered section jointed to one end of the first mounting section (58; 88; 242), wherein the tapered section has a first slit formed in its outer circumferential surface that extends through a tapered, annular wall of the tapered section; wherein the direction changing section further comprises a second slit formed in its outer circumferential surface, which extends through an annular wall of the direction changing section; and the second mounting section (62; 90; 208; 244; 306; 406; 512) is formed with a receiving bore in which the hub can be disposed; wherein the receiving bore is formed to be larger than a lumen of the intermediate section (60, 27, 404) in diameter; and a large diameter section of second mounting section (62; 90; 208; 244; 306; 406; 512) has a third slit formed in its outer circumferential surface which communicates with the receiving bore over substantially the entire length of the large diameter section, wherein the third slit gradually narrows in width as it extends radially toward the receiving bore, wherein the first slit, the second slit and the third slit together constitute a single slit. a first mounting section (58; 88; 242) that generally extends in first axial direction and being configured to allow a first portion of the tubular medical device (22, 28) to be received therein; a second mounting section (62; 90; 208; 244; 306; 406; 512) that generally extends in a second axial direction and being configured to allow a second portion of the tubular medical device (22, 28) to be received therein, the first and second mounting sections being fixed in spaced relation to each other with the first and second axial directions intersecting each other or being parallel to each other in plan view, so that with the first and second portions of the tubular medical device (22, 28) received therein, the first and second portions of the tubular medical device (22, 28) will extend in either transverse or parallel directions to each other; and an intermediate section (60, 27, 404) guiding the tubular medical device (22, 28) from the first mounting section (58; 88; 242) to the second mounting section (62; 90; 208; 244; 306; 406; 512); a tapered section jointed to one end of the first mounting section (58; 88; 242), wherein the tapered section has a first slit formed in its outer circumferential surface that extends through a tapered, annular wall of the tapered section; wherein the direction changing section further comprises a second slit formed in its outer circumferential surface, which extends through an annular wall of the direction changing section; and the second mounting section (62; 90; 208; 244; 306; 406; 512) is formed with a receiving bore in which the hub can be disposed; wherein the receiving bore is formed to be larger than a lumen of the intermediate section (60, 27, 404) in diameter; and a large diameter section of second mounting section (62; 90; 208; 244; 306; 406; 512) has a third slit formed in its outer circumferential surface which communicates with the receiving bore over substantially the entire length of the large diameter section, wherein the third slit gradually narrows in width as it extends radially toward the receiving bore, wherein the first slit, the second slit and the third slit together constitute a single slit.