An apparatus and a method for monitoring an object in a vehicle which recognize a state of an object from a different type of image through an artificial intelligence algorithm are disclosed. The in-vehicle object monitoring apparatus is an apparatus which monitors an in-vehicle object by using a first image and a second image, and comprises: an interface configured to receive a first image generated by a first camera in a vehicle and a second image generated by a second camera in the vehicle; and a processor configured to, when it is determined that there is an object in each of the first image and the second image, extract the first feature information about the object from the first image, extract the second feature information about the object from the second image, and recognize a state of the object, based on the first feature information and the second feature information.