A reclining device, comprising: a first bracket fixed to a seat cushion and having a predetermined number of outer teeth and a circular large-diameter hole concentric with the outer teeth; a second bracket fixed to a seat back, and having inner teeth in a larger number than the outer teeth to partially mesh with the outer teeth and a small-diameter shaft concentric with the inner teeth and fitted in the larger-diameter hole; a restriction member (16A, 16B) that restricts rotation of the second bracket in a specified direction and a counter direction, with the specified direction being a direction in which the second bracket rotates relative to the first bracket when the seat back is tilted backward and the counter direction being a direction in which the rotation opposite thereto is implemented; an operation member releasing the second bracket from restriction by the restriction member (16A, 16B) and allowing the second bracket to rotate in the specified direction or counter direction, thereby adjusting an attachment angle of the second bracket relative to the first bracket; and a rolling member provided in an eccentric cavity, the eccentric cavity being formed to have an uneven radial gap between a surrounding surface of the large-diameter hole of the first bracket and an outer circumferential surface of the small-diameter shaft of the second bracket, wherein the restriction member is a pair of wedge members (16A, 16B) provided at two circumferential locations in the eccentric cavity, with a spring member being engaged with the pair of wedge members (16A, 16B) to urge both wedge members (16A, 16B) in biting directions (f), the operation member includes a base part formed with a cut-out for accommodating the rolling member, and a protrusion protruding from the base part and arranged between ends in the biting directions (f) of the pair of wedge members (16A, 16B), the operation member pushing, by the protrusion, the pair of wedge members (16A, 16B) and the spring member in the specified direction or counter direction to impart an eccentric motion to the small-diameter shaft in the large-diameter hole and to change a mating position between the outer teeth and inner teeth, thereby adjusting the attachment angle of the second bracket, characterised in that the cut-out has a circumferential wall formed with a first wall pushing the rolling member in the specified direction when the operation member is rotated in the specified direction, and a second wall pushing the rolling member in the counter direction when the operation member is rotated in the counter direction, wherein at least one of the pair of wedge members located closer to an end in the specified direction of the protrusion has a slope at one end in a loosening direction, and the rolling member is arranged between ends in loosening directions of the pair of wedge members (16A, 16B), and is pushed up by the slope of the wedge member when a force is applied to the seat back in the backward tilting direction, then pressed against the surrounding surface of the large-diameter hole, thereby stopping rotation of the second bracket in the specified direction. a first bracket fixed to a seat cushion and having a predetermined number of outer teeth and a circular large-diameter hole concentric with the outer teeth; a second bracket fixed to a seat back, and having inner teeth in a larger number than the outer teeth to partially mesh with the outer teeth and a small-diameter shaft concentric with the inner teeth and fitted in the larger-diameter hole; a restriction member (16A, 16B) that restricts rotation of the second bracket in a specified direction and a counter direction, with the specified direction being a direction in which the second bracket rotates relative to the first bracket when the seat back is tilted backward and the counter direction being a direction in which the rotation opposite thereto is implemented; an operation member releasing the second bracket from restriction by the restriction member (16A, 16B) and allowing the second bracket to rotate in the specified direction or counter direction, thereby adjusting an attachment angle of the second bracket relative to the first bracket; and a rolling member provided in an eccentric cavity, the eccentric cavity being formed to have an uneven radial gap between a surrounding surface of the large-diameter hole of the first bracket and an outer circumferential surface of the small-diameter shaft of the second bracket, wherein the restriction member is a pair of wedge members (16A, 16B) provided at two circumferential locations in the eccentric cavity, with a spring member being engaged with the pair of wedge members (16A, 16B) to urge both wedge members (16A, 16B) in biting directions (f), the operation member includes a base part formed with a cut-out for accommodating the rolling member, and a protrusion protruding from the base part and arranged between ends in the biting directions (f) of the pair of wedge members (16A, 16B), the operation member pushing, by the protrusion, the pair of wedge members (16A, 16B) and the spring member in the specified direction or counter direction to impart an eccentric motion to the small-diameter shaft in the large-diameter hole and to change a mating position between the outer teeth and inner teeth, thereby adjusting the attachment angle of the second bracket,