A power transmission control device provided in a power transmission device included in a contactless power transmission system in which power is transmitted from the power transmission device to a power receiving device by electromagnetically coupling a primary coil and a secondary coil and the power is supplied to a load of the power receiving device includes a controller controlling the power transmission control device. The controller includes a communication condition setting section setting, by exchanging information with the power receiving device, a communication condition that is at least one of a communication method between the power transmission device and the power receiving device and a communication parameter, and a communication processing section performing a communication processing between the power transmission device and the power receiving device by using the set communication condition.