Foil bearing and rotating machine

A foil bearing comprising:

• a top foil that includes a bearing surface facing a shaft;
• a bump foil that supports the top foil from an outer periphery side of the top foil;
• and
• a tubular housing that accommodates the top foil and the bump foil,
• wherein the foil bearing includes a tubular portion that surrounds the bump foil and that supports the bump foil from an outer periphery side of the bump foil, and
• when in a cross section orthogonal to a central axis of the housing, a position of an upper end of an inner peripheral surface of the housing is defined as a position of 0° in a circumferential direction of the housing and a rotation direction of the shaft is defined as a positive direction of a position in the circumferential direction,
• in a state where the shaft rotates and floats from the bearing surface, in the cross section orthogonal to the central axis of the housing, an average value of distances between the central axis of the housing and an inner peripheral surface of the tubular portion in a range of 160° to 200° in the circumferential direction is smaller than an average value of distances between the central axis of the housing and the inner peripheral surface of the tubular portion in a range of 0° to 360° in the circumferential direction.