A rotary atomizing head type coating machine comprising: an air motor (3, 33) that uses compressed air as a power source; a hollow rotational shaft (5, 35) that is rotatably supported by said air motor (3, 33) and a tip end of which projects to a front side from said air motor (3, 33); a feed tube (6, 36) that extends to the tip end of said rotational shaft (5, 35) through in said rotational shaft (5, 35) to supply paint or wash fluid; a rotary atomizing head (7, 37) a base end side of which is formed of a cylindrical section (7A, 37A) mounted to the tip end of said rotational shaft (5, 35) and a portion closer to a front side than said cylindrical section (7A, 37A) of which is formed of a cup section (7B, 37B) enlarged in a cup shape to spray paint from a tip end of said cup section (7B, 37B); a shaping air ring (15, 44) that is arranged on an outer peripheral side of said rotary atomizing head (7, 37), has a ring inner peripheral surface (17B, 46B) facing an atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37) with an annular clearance (20, 49), and has many shaping air spurting holes (18, 19, 47, 48) on a front end surface (17A, 46A) to spurt shaping air; and an assist air spurting hole (21, 50) that is provided to open to said ring inner peripheral surface (17B, 46B) of said shaping air ring (15, 44) and spurts assist air into said annular clearance (20, 49) defined between said ring inner peripheral surface (17B, 46B) and said atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37), wherein said rotary atomizing head (7, 37) is provided with an outer peripheral surface washing passage (14, 43, 61) open onto said atomizing head outer peripheral surface (13, 42) for causing said wash fluid supplied from said feed tube (6, 36) to flow out into said annular clearance (20, 49), characterized in that an outflow opening (14C1, 43B, 61A1) of said outer peripheral surface washing passage (14, 43, 61) is provided in a position closer to the backside into said annular clearance (20, 49) than a tip end of said shaping air ring (15, 44) and opens into said annular clearance (20, 49) in an angle (α1, α2, α3) that is an acute angle to said atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37). an air motor (3, 33) that uses compressed air as a power source; a hollow rotational shaft (5, 35) that is rotatably supported by said air motor (3, 33) and a tip end of which projects to a front side from said air motor (3, 33); a feed tube (6, 36) that extends to the tip end of said rotational shaft (5, 35) through in said rotational shaft (5, 35) to supply paint or wash fluid; a rotary atomizing head (7, 37) a base end side of which is formed of a cylindrical section (7A, 37A) mounted to the tip end of said rotational shaft (5, 35) and a portion closer to a front side than said cylindrical section (7A, 37A) of which is formed of a cup section (7B, 37B) enlarged in a cup shape to spray paint from a tip end of said cup section (7B, 37B); a shaping air ring (15, 44) that is arranged on an outer peripheral side of said rotary atomizing head (7, 37), has a ring inner peripheral surface (17B, 46B) facing an atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37) with an annular clearance (20, 49), and has many shaping air spurting holes (18, 19, 47, 48) on a front end surface (17A, 46A) to spurt shaping air; and an assist air spurting hole (21, 50) that is provided to open to said ring inner peripheral surface (17B, 46B) of said shaping air ring (15, 44) and spurts assist air into said annular clearance (20, 49) defined between said ring inner peripheral surface (17B, 46B) and said atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37), wherein said rotary atomizing head (7, 37) is provided with an outer peripheral surface washing passage (14, 43, 61) open onto said atomizing head outer peripheral surface (13, 42) for causing said wash fluid supplied from said feed tube (6, 36) to flow out into said annular clearance (20, 49), characterized in that an outflow opening (14C1, 43B, 61A1) of said outer peripheral surface washing passage (14, 43, 61) is provided in a position closer to the backside into said annular clearance (20, 49) than a tip end of said shaping air ring (15, 44) and opens into said annular clearance (20, 49) in an angle (α1, α2, α3) that is an acute angle to said atomizing head outer peripheral surface (13, 42) of said rotary atomizing head (7, 37).