PURPOSE: To prevent a moving object from following an erroneous course, by recording absolute position information on a recording medium in accordance with manual setting of absolute position information indicating a preliminarily determined position.

CONSTITUTION: Rotation shafts of rear wheels RW1 and RW2 of a car or the like which are rotated and driven independently of each other are provided with pulse generators PG1 and PG2, respectively. A counter (CT) 1 counts the output of the pulse generator PG1 and inputs the counted value to multipliers M1 and M2 to calculate a movement distance. A CT3 detects the difference between outputs of pulse generators PG1 and PG2 and gives it to a correcting circuit CRT1, and this difference is given to a sine circuit SIN and a cosine circuit COS through a correcting circuit CRT2 and is multiplied in multipliers M1 and M2 and is displayed on an XY recorder XYR as a movement course. When absolute position information is set to a set switch SSW, this information is given to the circuit CRT2 through a bearing signal generator SG to initialize it correctively. Thus, an absolute position is detected on the recorder to prevent erroneous movement.