TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred System: The system includes a condenser for condensing the fuel recovered by the recovery passage, a gas-liquid separator for separating the recovered fuel into gaseous phase fuel and liquid phase fuel, a second fuel tank for collecting the liquid phase fuel and a second pump for supplying fuel in the second fuel tank to the vaporizer. The vaporizer has an injector for injecting liquid fuel supplied from the fuel tank in the heating element. The recovery passage recovers fuel in a gas-liquid mixed state formed in the heating element. It has a fuel passage having an upstream part and downstream part disposed in parallel, and a curved middle part connecting the upstream and downstream parts. The upstream and downstream parts are heated by the heating element. A heat insulating material blocks transmission of heat between the upstream and downstream parts. The passages of the recovery passage are connected to the middle part and upstream part of the fuel passage. A relief valve (14) relieves a pressure higher than a predetermined pressure in the vaporizer. The system includes a first valve (17) for opening and closing the vapor supply passage, a second valve (18) for opening and closing the recovery passage, a sensor for detecting a running condition of a drive vehicle, and a controller for controlling an opening of the second valve and an operation of the heating element based on the running condition of the vehicle. The controller applies standby modes to the fuel reforming system in a state where a supply of liquid hydrocarbon fuel into the vaporizer is stopped and the first valve is closed. In a first standby mode, the second valve is closed while the heating element is kept activated and in a second standby mode, the second valve is opened while the heating element is kept activated. In a third standby mode, the second valve is opened while the heating element is deactivated. The sensor has a vehicle navigation system for detecting information relating to a vehicle route.