In a shift control device operative to determine shift positions based on an absolute positional information related to a mechanical displacement of a shift mechanism, it is intended that the shift positions are accurately determined regardless of disturbance and deterioration with time. It is determined as to whether a varying width of a position voltage PV representing absolute positional information relative to a varying width of a pulse count number CP representing relative positional information is larger than an varying allowable range. When a state, under which difference between the both variations is larger than the varying allowable range, continues beyond a determining time T, a determination is made that persistent disturbance is existed in the position voltage PV, and a correlation between the position voltage PV and the shift positions “P”, “R”, “N” and “D” is learnt and corrected. This allows the correlation to be corrected even if a variation occurs in the position voltage PV due to for instance variations in a disturbance magnetic field or an environmental temperature, a change with time of an output characteristic of a hall element 78, so that the shift position can be determined based on the position voltage PV with increased precision at all times.