A gearshift device comprising an operation member and a position sensor that is configured to detect operation positions (P;R;N;D;S) of the operation member, the position sensor comprising: an element array including at least three stages arranged in columns, wherein each stage corresponding to one column includes one or more detection elements; a single detected subject in the form of a magnet that is arranged on the operation member and moves in cooperation with the movement of the operation member, wherein the detected subject is configured such that presence of the detected subject can be simultaneously detected, for each of the operation positions (P;R;N;D;S), by each of the detection elements included in two adjacent stages of the element array that are an upstream side stage and a downstream side stage to determine one operation position of the operation member, wherein each of the detection elements of the element array is configured to detect the presence or absence of the detected subject and output a detection result indicating a detection result ON when detecting the detected subject and a detection result OFF when not detecting the detected subject, characterized in that whenever the operation member is shifted by one operation position, the detected subject is moved relative to the element array toward the downstream side by one stage, wherein the element array is arranged such that the detection results of at least three of the detection elements of the element array change whenever the operation member is shifted by one operation position, and the at least three of the detection elements include at least one detection element in the upstream side stage that is able to detect the detected subject before the operation member is shifted by one operation position, and at least one detection element in the downstream side stage that is able to detect the detected subject after the operation member is shifted by one operation position. an element array including at least three stages arranged in columns, wherein each stage corresponding to one column includes one or more detection elements; a single detected subject in the form of a magnet that is arranged on the operation member and moves in cooperation with the movement of the operation member, wherein the detected subject is configured such that presence of the detected subject can be simultaneously detected, for each of the operation positions (P;R;N;D;S), by each of the detection elements included in two adjacent stages of the element array that are an upstream side stage and a downstream side stage to determine one operation position of the operation member, wherein each of the detection elements of the element array is configured to detect the presence or absence of the detected subject and output a detection result indicating a detection result ON when detecting the detected subject and a detection result OFF when not detecting the detected subject, characterized in that whenever the operation member is shifted by one operation position, the detected subject is moved relative to the element array toward the downstream side by one stage, wherein the element array is arranged such that the detection results of at least three of the detection elements of the element array change whenever the operation member is shifted by one operation position, and the at least three of the detection elements include at least one detection element in the upstream side stage that is able to detect the detected subject before the operation member is shifted by one operation position, and at least one detection element in the downstream side stage that is able to detect the detected subject after the operation member is shifted by one operation position. at least one detection element in the upstream side stage that is able to detect the detected subject before the operation member is shifted by one operation position, and at least one detection element in the downstream side stage that is able to detect the detected subject after the operation member is shifted by one operation position.