A radial foil bearing (3, 40, 50) used for supporting a rotary shaft so as to encircle the rotary shaft, the radial foil bearing (3, 40, 50) comprising: a cylindrical top foil disposed so as to face the rotary shaft; an intermediate foil (10, 41) disposed outside of the top foil in a radial direction thereof; a back foil disposed outside of the intermediate foil (10, 41) in the radial direction; and a cylindrical bearing housing (12, 42, 51) accommodating the top foil, the intermediate foil (10, 41) and the back foil, wherein the intermediate foil (10, 41) includes intermediate foil pieces (10a, 41a) disposed in the circumferential direction of the bearing housing (12, 42, 51), and wherein an engagement-projecting piece (10b, 41b) is formed in each intermediate foil piece (10a, 41a), characterised in that the top foil is formed by winding a rectangular metal foil into a cylindrical shape, a first uneven portion is formed in one side of the top foil, wherein the first uneven portion includes one projecting portion and two depressed portions, and a second uneven portion is formed in the other side opposite to the one side, wherein the second uneven portion includes two projecting portions and one depressed portion, the depressed portion of the second uneven portion is formed so as to correspond to the projecting portion of the first uneven portion, and the depressed portions of the first uneven portion are formed so as to correspond to the projecting portions of the second uneven portion, the depressed portion of the second uneven portion being formed so that the projecting portion passes through the depressed portion when the top foil is wound in the cylindrical shape in which the first and second uneven portions (23a, 23b) overlap with each other, and the depressed portions of the first uneven portion are formed so that the projecting portions pass through the depressed portions when the top foil is wound in the cylindrical shape, and a plurality of pairs of engagement recesses (31, 35) are formed in the bearing housing (12, 42, 51), each pair of engagement recesses (31, 35) are positioned on both side surfaces of the bearing housing (12, 42, 51) so as to be opposite to each other, each engagement recess (31, 35) extends from an inner circumferential surface toward an outer circumferential surface of the bearing housing (12, 42, 51), the engagement-projecting pieces (10b, 41b) of the intermediate foil pieces (10a, 41a) engaging with respective engagement recesses (31, 35) and the plurality of pairs of engagement recesses (31, 35) are disposed in a circumferential direction of the bearing housing (12, 42, 51). a cylindrical top foil disposed so as to face the rotary shaft; an intermediate foil (10, 41) disposed outside of the top foil in a radial direction thereof; a back foil disposed outside of the intermediate foil (10, 41) in the radial direction; and a cylindrical bearing housing (12, 42, 51) accommodating the top foil, the intermediate foil (10, 41) and the back foil, wherein the intermediate foil (10, 41) includes intermediate foil pieces (10a, 41a) disposed in the circumferential direction of the bearing housing (12, 42, 51), and wherein an engagement-projecting piece (10b, 41b) is formed in each intermediate foil piece (10a, 41a), characterised in that the top foil is formed by winding a rectangular metal foil into a cylindrical shape, a first uneven portion is formed in one side of the top foil, wherein the first uneven portion includes one projecting portion and two depressed portions, and a second uneven portion is formed in the other side opposite to the one side, wherein the second uneven portion includes two projecting portions and one depressed portion, the depressed portion of the second uneven portion is formed so as to correspond to the projecting portion of the first uneven portion, and the depressed portions of the first uneven portion are formed so as to correspond to the projecting portions of the second uneven portion, the depressed portion of the second uneven portion being formed so that the projecting portion passes through the depressed portion when the top foil is wound in the cylindrical shape in which the first and second uneven portions (23a, 23b) overlap with each other, and the depressed portions of the first uneven portion are formed so that the projecting portions pass through the depressed portions when the top foil is wound in the cylindrical shape, and a plurality of pairs of engagement recesses (31, 35) are formed in the bearing housing (12, 42, 51), each pair of engagement recesses (31, 35) are positioned on both side surfaces of the bearing housing (12, 42, 51) so as to be opposite to each other, each engagement recess (31, 35) extends from an inner circumferential surface toward an outer circumferential surface of the bearing housing (12, 42, 51), the engagement-projecting pieces (10b, 41b) of the intermediate foil pieces (10a, 41a) engaging with respective engagement recesses (31, 35) and the plurality of pairs of engagement recesses (31, 35) are disposed in a circumferential direction of the bearing housing (12, 42, 51).