A power transmission control device used for a non-contact power transmission system includes a power-transmitting-side control circuit that controls power transmission to a power receiving device, a calculation circuit that calculates the position of a secondary coil by performing given calculations, and an actuator control circuit that controls the operation of an actuator, the actuator moving the position of the primary coil in an XY plane, the actuator control circuit scanning the primary coil for detecting the position of the secondary coil L2, the calculation circuit performing the given calculations based on data acquired by the scan for detecting the position of the secondary coil L2 to determine the position of the secondary coil L2, and the actuator control circuit moving the primary coil L1 so that the position of the primary coil coincides with the calculated position of the secondary coil.