A power transmission control device used for a non-contact power transmission system includes an operation mode switching terminal that receives an operation mode switch control signal that switches a mode between an automatic mode and a switch mode, a power transmitting device starting normal power transmission in the automatic mode after installation of a power-receiving-side instrument that includes a power receiving device in an area in which power transmitted via non-contact power transmission can be received has been automatically detected, the normal power transmission supplying power to a load of the power-receiving-side instrument, and the power transmitting device starting the normal power transmission in the switch mode after an operation trigger switch has been turned ON, an operation trigger terminal that receives an operation trigger signal that occurs due to an operation of the operation trigger switch, and a power-transmitting-side control circuit that controls power transmission to the power receiving device and changes an operation mode of the power transmitting device based on the operation mode switch control signal.