A drive assist device comprising: an overhead image generating unit that generates a vehicle periphery overhead image as a display image of the periphery of a vehicle displayed in a monitor, by performing viewpoint conversion from a captured image obtained by a camera that captures the periphery of the vehicle; a steering angle calculation unit that calculates a steering angle of the vehicle; a forward trajectory setting unit that sets a forward trajectory serving as an expected trajectory in the travel direction of the vehicle when turning based on the calculated steering angle calculated by the steering angle calculation unit; a reverse trajectory setting unit that sets a reverse trajectory serving as an expected trajectory in the travel direction of the vehicle or the opposite direction as the travel direction of the vehicle when turning based on a steering angle in the opposite direction as the calculated steering angle; and an image synthesizing unit that generates a drive assist overhead image for display in a monitor by synthesizing the forward trajectory and the reverse trajectory with the vehicle periphery overhead image, so that a vehicle image in the vehicle periphery overhead image serves as a departure point, characterized in that an expected trajectory in the travel direction of the vehicle is set as the reverse trajectory during same-direction reverse-steering travel, and an expected trajectory in the opposite direction as the travel direction of the vehicle is set as the reverse trajectory during opposite-direction reverse-steering travel, wherein the forward trajectory and the reverse trajectory are displayed in the monitor in formats that are different from each other visually. an overhead image generating unit that generates a vehicle periphery overhead image as a display image of the periphery of a vehicle displayed in a monitor, by performing viewpoint conversion from a captured image obtained by a camera that captures the periphery of the vehicle; a steering angle calculation unit that calculates a steering angle of the vehicle; a forward trajectory setting unit that sets a forward trajectory serving as an expected trajectory in the travel direction of the vehicle when turning based on the calculated steering angle calculated by the steering angle calculation unit; a reverse trajectory setting unit that sets a reverse trajectory serving as an expected trajectory in the travel direction of the vehicle or the opposite direction as the travel direction of the vehicle when turning based on a steering angle in the opposite direction as the calculated steering angle; and an image synthesizing unit that generates a drive assist overhead image for display in a monitor by synthesizing the forward trajectory and the reverse trajectory with the vehicle periphery overhead image, so that a vehicle image in the vehicle periphery overhead image serves as a departure point, characterized in that an expected trajectory in the travel direction of the vehicle is set as the reverse trajectory during same-direction reverse-steering travel, and an expected trajectory in the opposite direction as the travel direction of the vehicle is set as the reverse trajectory during opposite-direction reverse-steering travel, wherein the forward trajectory and the reverse trajectory are displayed in the monitor in formats that are different from each other visually.