PURPOSE: To provide a device and a method for detecting an angle whereby an accurate rotational angle is detected in a continuously rotating unit.

CONSTITUTION: In an angle detecting device 1 and an angle detecting method for detecting an angle of a rotating unit 2 continuously rotating by driving a motor 3, a pulse signal is generated in an encoder 4 synchronized with rotating the motor 3, and also the original point relating to moving the rotating unit 2 is detected by an original point sensor 5, to integrate a number of the pulse signals from the original point in each rotating of the rotating unit 2 in a high speed counter 6. Based on a number of the pulse signals integrated by this high speed counter 6, a rotary angle relating to the original point of the rotating unit 2 is calculated in a controller 7.