A spindle apparatus (10, 110A) comprising: a rotary shaft (11, 111); a front bearing (50, 150) supporting the rotary shaft (11, 111), a housing (H, 100H) rotatably supporting the rotary shaft (11, 111) via the bearing (50, 150); and a flinger (40, 40B, 40C, 40D, 140) fixed to the rotary shaft (11, 111) in an integrally rotatable manner and forming at least a portion of a waterproof mechanism that prevents a liquid from entering the bearing (50, 150), wherein the flinger (40, 40B, 40C, 40D, 140) comprises a base portion (41, 141) fixed on the rotary shaft (11, 111), a disk portion (42, 142) extending radially outward from the base portion (41, 141) and arranged to be axially opposed to an axial end surface (71, 171) of the housing (H, 100H) with a slight gap therebetween, and an annular portion (43, 143) axially extending from the disk portion (42, 142) and arranged to be radially opposed to an outer peripheral surface (75, 175, 193) of the housing (H, 100H) with a slight gap therebetween, and at least one circumferential groove (79, 179) is provided in a recessed manner on an opposing surface of the outer peripheral surface (75, 193) of the housing that is radially opposed to the annular portion (43, 143), characterized in that the annular portion (43, 143) has a tapered shape, a thickness of which is reduced along an axial direction away from the disk portion (42, 142), and an inner peripheral surface (48, 145) of the annular portion (43, 143) is a tapered surface, a radial distance of which from the rotary shaft (11, 111) is increased along an axial direction away from the disk portion (42, 142) of the flinger (40C, 140). a rotary shaft (11, 111); a front bearing (50, 150) supporting the rotary shaft (11, 111), a housing (H, 100H) rotatably supporting the rotary shaft (11, 111) via the bearing (50, 150); and a flinger (40, 40B, 40C, 40D, 140) fixed to the rotary shaft (11, 111) in an integrally rotatable manner and forming at least a portion of a waterproof mechanism that prevents a liquid from entering the bearing (50, 150), wherein the flinger (40, 40B, 40C, 40D, 140) comprises a base portion (41, 141) fixed on the rotary shaft (11, 111), a disk portion (42, 142) extending radially outward from the base portion (41, 141) and arranged to be axially opposed to an axial end surface (71, 171) of the housing (H, 100H) with a slight gap therebetween, and an annular portion (43, 143) axially extending from the disk portion (42, 142) and arranged to be radially opposed to an outer peripheral surface (75, 175, 193) of the housing (H, 100H) with a slight gap therebetween, and at least one circumferential groove (79, 179) is provided in a recessed manner on an opposing surface of the outer peripheral surface (75, 193) of the housing that is radially opposed to the annular portion (43, 143), characterized in that the annular portion (43, 143) has a tapered shape, a thickness of which is reduced along an axial direction away from the disk portion (42, 142), and an inner peripheral surface (48, 145) of the annular portion (43, 143) is a tapered surface, a radial distance of which from the rotary shaft (11, 111) is increased along an axial direction away from the disk portion (42, 142) of the flinger (40C, 140).