A turbofan engine includes: a cylindrical fan case; a fan rotatably disposed in the fan case and including a central member and multiple fan blades arranged on an outer circumference of the central member such that the fan blades are spaced apart from one another in a circumferential direction; an annular member disposed to surround the fan; and an elastic support device that supports the annular member to the fan case radially elastically such that a predetermined clearance is radially defined between the annular member and tips of the fan blades.