A position sensor that detects operation positions of an operation member includes an element array having three stages, each including one or more detection elements. A detected subject is detected by each detection element in two adjacent upstream and downstream stages to determine an operation position of the operation member. Whenever the operation member is shifted by one operation position, the detected subject is moved relative to the element array by one stage. Each detection element outputs a detection result of the detected subject. The element array includes at least three detection elements of which the detection results change whenever the operation member is shifted by one operation position. A detection element in the upstream side stage detects the detected subject before the operation position shifting, and a detection element in the downstream side stage detects the detected subject after the operation position shifting.