<p>An electronic device mounting structure for fitting an ECU 2 (electronic device) in an open space 4 formed in a device mounting housing 1 and for holding the ECU fitted in the open space 4 by a holding finger 9 formed on the device mounting housing 1, includes a stopper 10 formed in the device mounting housing 1 so as to be juxtaposed with the holding finger 9, the stopper being configured to prevent the ECU 2 from falling out of the device mounting housing 1.</p>