A collision avoidance apparatus capable of executing an appropriate vehicle control in order to avoid a collision between an own vehicle and a movable object is provided. A collision avoidance apparatus for avoiding a collision between an own vehicle and a movable object includes: a laterally-existing movable object detector for detecting for a movable object that approaches from a direction lateral to the own vehicle; a side collision determination section for determining whether or not a risk that the own vehicle and the movable object collide with each other is high, when the laterally-existing movable object detector has detected the movable object that approaches from the direction lateral to the own vehicle; a passage and avoidance determination section for determining, when the risk that the own vehicle and the movable object collide with each other is determined to be high, whether or not a possibility that a collision between the own vehicle and the movable object can be avoided by the own vehicle passing in front of the movable object, is high; and an accelerated state/decelerated state controller for controlling the own vehicle to be in one of an accelerated state and a decelerated state, according to a determination result of the passage and avoidance determination section.