A vehicle driving assist system comprising: a travelling situation detecting section (10, 30) configured to output a travelling situation detection result based on at least a distance between a host vehicle and an obstacle existing in front of the host vehicle and a speed of the host vehicle; a relative position calculating section configured to calculate a positional relationship between the host vehicle and the obstacle based on the travelling situation detection result of the travelling situation detecting section (10, 30); a risk potential calculating section configured to calculate a risk potential that indicates a degree of convergence between the host vehicle and the obstacle based on the travelling situation detection result of the travelling situation detecting section (10, 30); and a control section (55, 57, 70, 73, 93) configured to control at least one of an actuation reaction force exerted by the accelerator pedal and a braking/driving force exerted against the host vehicle based on the risk potential calculated by the risk potential calculating section; characterised in that the vehicle driving assist system further comprises: an accelerator pedal actuation state detecting section configured to detect an accelerator pedal actuation state of an accelerator pedal of the host vehicle by a driver; a driver intent predicting section configured to predict whether a driver's intention is to accelerate, decelerate, or travel at a constant speed based on the accelerator pedal actuation state detected by the accelerator pedal actuation state detecting section; and a control pattern selecting section configured to select a selected vehicle control pattern from among a plurality of vehicle control patterns based on the accelerator pedal actuation state detected by the accelerator pedal actuation state detecting section and the positional relationship between the host vehicle and the obstacle calculated by the relative position calculating section; wherein the risk potential calculating section is further configured to execute the calculation of the risk potential in accordance with the selected vehicle control pattern selected by the control pattern selecting section. a travelling situation detecting section (10, 30) configured to output a travelling situation detection result based on at least a distance between a host vehicle and an obstacle existing in front of the host vehicle and a speed of the host vehicle; a relative position calculating section configured to calculate a positional relationship between the host vehicle and the obstacle based on the travelling situation detection result of the travelling situation detecting section (10, 30); a risk potential calculating section configured to calculate a risk potential that indicates a degree of convergence between the host vehicle and the obstacle based on the travelling situation detection result of the travelling situation detecting section (10, 30); and a control section (55, 57, 70, 73, 93) configured to control at least one of an actuation reaction force exerted by the accelerator pedal and a braking/driving force exerted against the host vehicle based on the risk potential calculated by the risk potential calculating section; an accelerator pedal actuation state detecting section configured to detect an accelerator pedal actuation state of an accelerator pedal of the host vehicle by a driver; a driver intent predicting section configured to predict whether a driver's intention is to accelerate, decelerate, or travel at a constant speed based on the accelerator pedal actuation state detected by the accelerator pedal actuation state detecting section; and a control pattern selecting section configured to select a selected vehicle control pattern from among a plurality of vehicle control patterns based on the accelerator pedal actuation state detected by the accelerator pedal actuation state detecting section and the positional relationship between the host vehicle and the obstacle calculated by the relative position calculating section; wherein the risk potential calculating section is further configured to execute the calculation of the risk potential in accordance with the selected vehicle control pattern selected by the control pattern selecting section.