An absolute encoder includes a circuit board disposed away from a rotation shaft of a motor in a shaft direction of the rotation shaft thereof, the circuit board being fixed to top end surfaces of multiple pillars each extending from a motor side, by respective locking sections. The absolute encoder includes a sensor disposed, on the circuit board, facing a rotating body that rotates in accordance with rotation of the rotation shaft, the sensor being configured to detect a rotation amount of the rotating body. The circuit board includes first fixing portions each fixed to a top end surface of a given pillar, by a corresponding locking section. The circuit board includes a second fixing portion fixed to a top end surface of a given pillar by a corresponding locking section, the second fixing portion being connected to a ground. At each of the first fixing portions, an adjustment portion is disposed between the circuit board and a top end portion of a given pillar is provided, the adjustment portion being set to adjust a distance between the circuit board and the top end portion of the given pillar, so that a height of the circuit board at a given first fixing portion is set to be the same as a height of the circuit board at the second fixing portion.