Measuring device and measuring method

A measuring method using a measuring device having:

• a rotary encoder having a rotary scale and a plurality of detection portions, the rotary scale being arranged around a rotation axis and having a scale pattern in which a plurality of patterns are arranged along a circumferential direction, the plurality of detection portions being arranged around the rotation axis and each facing the rotary scale and reading the plurality of patterns from the scale pattern;
• and a control device configured to control the rotary encoder,
• the method comprising:
• performing a first reading of the plurality of patterns using one or some detection portions among the plurality of detection portions at a first timing;
• performing a second reading of the plurality of patterns using another or other detection portions different from the one or some detection portions at a second timing different from the first timing;
• and
• calculating a measurement result based on a first reading result of the first reading and a second reading result of the second reading.