This relates to a radial foil bearing (3) that supports a rotating shaft (1). The radial foil bearing (3) is provided with a top foil (10), a back foil (11), and a bearing housing (12) that houses them. An engagement notch (15) that extends from the inner circumferential edge to the outer circumferential edge of the bearing housing (12) is formed at both sides of the bearing housing (12). An engagement protruding piece (30) that engages with each engagement notch (15) is provided at both side end portions of the back foil (11) on one side in the circumferential direction of the bearing housing (12).