A movable body drive method in which a movable body is driven along a predetermined plane including a first axis and a second axis orthogonal to each other, the method comprising: a first process in which a position of the movable body within the predetermined plane is controlled, based on measurement values of a set of heads of an encoder (70A-F) including three heads among a plurality of first heads (66 1 - 5)whose positions in a direction parallel to the second axis are different and a plurality of second heads (64 1-5) whose positions in a direction parallel to the first axis are different, with the three heads respectively facing three gratings selected from a pair of first gratings (39X 1/2) whose periodic direction is in a direction parallel to the first axis and a pair of second gratings (39Y 1/2) whose periodic direction is in a direction parallel to the second axis that are arranged on a surface parallel to the predetermined plane of the movable body; and a second process in which a set of heads used in position control of the movable body is switched to a different set of heads including three heads that have at least one head which is different from the set of heads, characterized by the method further comprising: a third process in which a set of heads used in position control of the movable body is switched to a different set of heads including three heads that have at least one head which is different from the set of heads, whilst not resetting a phase offset and continuously using the phase offset which is already set and whilst resetting a count value. a first process in which a position of the movable body within the predetermined plane is controlled, based on measurement values of a set of heads of an encoder (70A-F) including three heads among a plurality of first heads (66 1 - 5)whose positions in a direction parallel to the second axis are different and a plurality of second heads (64 1-5) whose positions in a direction parallel to the first axis are different, with the three heads respectively facing three gratings selected from a pair of first gratings (39X 1/2) whose periodic direction is in a direction parallel to the first axis and a pair of second gratings (39Y 1/2) whose periodic direction is in a direction parallel to the second axis that are arranged on a surface parallel to the predetermined plane of the movable body; and a second process in which a set of heads used in position control of the movable body is switched to a different set of heads including three heads that have at least one head which is different from the set of heads, characterized by the method further comprising: a third process in which a set of heads used in position control of the movable body is switched to a different set of heads including three heads that have at least one head which is different from the set of heads, whilst not resetting a phase offset and continuously using the phase offset which is already set and whilst resetting a count value. a third process in which a set of heads used in position control of the movable body is switched to a different set of heads including three heads that have at least one head which is different from the set of heads, whilst not resetting a phase offset and continuously using the phase offset which is already set and whilst resetting a count value.