A collision avoidance apparatus includes a travelling state calculation section, a target detection section, a target state calculation section, a lateral moving object determination section, a collision determination section, and a collision avoidance control section. The collision avoidance control section calculates, based on (i) a passing-through period of the lateral moving object in which the lateral moving object passes through an own vehicle course that is a moving course of the own vehicle and (ii) a reaching time of the own vehicle that is a period remaining before the own vehicle reaching a lateral moving object course that is a moving course of the lateral moving object, an operation timing of the brakes for the lateral moving object passing through the own vehicle course before the own vehicle reaches the lateral moving object course, and operates the brakes at the calculated operation timing of the brakes.