A drive assistance apparatus includes a target trajectory setting unit configured to set a target trajectory in a lane change assistance based on a movement time taken for a vehicle of which the direction indicator is continued to be in ON-state to move a lateral distance set in advance to the adjacent lane side from an operation start lateral position, and a lane change assistance unit configured to execute the lane change assistance for causing the vehicle to change lane along the target trajectory in a case where the lateral position of the vehicle of which the direction indicator is continued to be in ON-state reaches the assistance start lateral position set in advance in the travelling lane from the setting of the target trajectory by the target trajectory setting unit.