An electromechanical device comprising: a motor comprising a rotation shaft and the motor is configured to apply, to the rotation shaft, a torque toward an angular position in accordance with control; a rotation sensor configured to detect the angular position of the rotation shaft; and a motor controller configured to control rotational speed of the rotation shaft depending on the angular position detected by the rotation sensor, wherein the motor controller is configured to determine, based on the angular position detected by the rotation sensor, whether a rotation start position of the rotation shaft is a predetermined normal rotation start position, wherein, upon determining that the rotation start position is a middle start position other than the predetermined normal rotation start position, the motor controller is configured to identify a relative target rotational speed corresponding to the detected angular position using a relative pattern that defines, using the middle start position as a starting point of the relative pattern, relations between the angular position and the relative target rotational speed, and the motor controller is configured to control the rotational speed of the rotation shaft using the identified relative target rotational speed, characterised in that the motor controller is configured to use an absolute pattern that defines, using the normal rotation start position as a starting point of the absolute pattern, relations between the angular position and an absolute target rotational speed to identify the absolute target rotational speed corresponding to the detected angular position, wherein, upon detecting that a condition that the identified absolute target rotational speed is greater than the relative target rotational speed corresponding to the detected angular position is not satisfied, the motor controller Z is configured to control the rotational speed of the rotation shaft using the identified absolute target rotational speed, and the motor controller is configured to generate the relative pattern based on the absolute pattern in a way that the relative pattern and the absolute pattern have an identical shape at all middle start positions. a motor comprising a rotation shaft and the motor is configured to apply, to the rotation shaft, a torque toward an angular position in accordance with control; a rotation sensor configured to detect the angular position of the rotation shaft; and a motor controller configured to control rotational speed of the rotation shaft depending on the angular position detected by the rotation sensor, wherein the motor controller is configured to determine, based on the angular position detected by the rotation sensor, whether a rotation start position of the rotation shaft is a predetermined normal rotation start position, wherein, upon determining that the rotation start position is a middle start position other than the predetermined normal rotation start position, the motor controller is configured to identify a relative target rotational speed corresponding to the detected angular position using a relative pattern that defines, using the middle start position as a starting point of the relative pattern, relations between the angular position and the relative target rotational speed, and the motor controller is configured to control the rotational speed of the rotation shaft using the identified relative target rotational speed, characterised in that the motor controller is configured to use an absolute pattern that defines, using the normal rotation start position as a starting point of the absolute pattern, relations between the angular position and an absolute target rotational speed to identify the absolute target rotational speed corresponding to the detected angular position, wherein, upon detecting that a condition that the identified absolute target rotational speed is greater than the relative target rotational speed corresponding to the detected angular position is not satisfied, the motor controller Z is configured to control the rotational speed of the rotation shaft using the identified absolute target rotational speed, and the motor controller is configured to generate the relative pattern based on the absolute pattern in a way that the relative pattern and the absolute pattern have an identical shape at all middle start positions.