An angle detection apparatus characterized by comprising: a rotating body (20, 120); another rotating body (24, 122); a transmission mechanism (18, 111) that is configured to cause the other rotating body (24, 122) to rotate by reducing a speed of a rotation of the rotating body (20, 120); an angle detector that is configured to detect a rotational angle of the rotating body (20, 120); another angle detector that is configured to detect a rotational angle of the other rotating body (24, 122); and a processor that is configured to specify a number of revolutions of the rotating body (20, 120), wherein the processor is configured to specify the number of revolutions while dynamically varying a specification condition for specifying the number of revolutions according to a numerical value decided according to the detected rotational angle of the rotating body (20, 120) and a reduction ratio of the transmission mechanism (18, 111), and the detected rotational angle of the other rotating body (24, 122), wherein the processor is configured to set a lower limit value and an upper limit value according to the detected rotational angle of the rotating body (20, 120), and the processor is configured to set a condition of being the lower limit value or greater and also less than the upper limit value as the specification condition, wherein in the case where the detected rotational angle of the other rotating body (24, 122) satisfies one of the specification conditions, the processor specifies the number of revolutions corresponding to that specification condition as the number of revolutions of the rotating body (20, 120). a rotating body (20, 120); another rotating body (24, 122); a transmission mechanism (18, 111) that is configured to cause the other rotating body (24, 122) to rotate by reducing a speed of a rotation of the rotating body (20, 120); an angle detector that is configured to detect a rotational angle of the rotating body (20, 120); another angle detector that is configured to detect a rotational angle of the other rotating body (24, 122); and a processor that is configured to specify a number of revolutions of the rotating body (20, 120), wherein the processor is configured to specify the number of revolutions while dynamically varying a specification condition for specifying the number of revolutions according to a numerical value decided according to the detected rotational angle of the rotating body (20, 120) and a reduction ratio of the transmission mechanism (18, 111), and the detected rotational angle of the other rotating body (24, 122), wherein the processor is configured to set a lower limit value and an upper limit value according to the detected rotational angle of the rotating body (20, 120), and the processor is configured to set a condition of being the lower limit value or greater and also less than the upper limit value as the specification condition, wherein in the case where the detected rotational angle of the other rotating body (24, 122) satisfies one of the specification conditions, the processor specifies the number of revolutions corresponding to that specification condition as the number of revolutions of the rotating body (20, 120).