The embodiments of the invention provide a washing machine automatic putting-in prompting device and methods and automatic putting-in washing machines, and belongs to the technical field of washing machine automatic putting-in. The automatic putting-in prompting device includes a detection unit which is used for detecting automatic putting-in information, wherein the automatic putting-in information includes remaining amount of detergent, and a triggering determination unit which is used for determining whether to generate a prompt triggering instruction according to the automatic putting-in information so as to determine whether to trigger the execution a prompting action. Since the remaining amount information of the detergent is obtained by detection, a washing machine user can more conveniently know use conditions of the detergent. Moreover, the prompt action can be triggered according to the remaining amount information, and the user can be timely prompted to take measures when the remaining amount of the detergent does not meet certain requirements, and so the hidden danger of not adding the detergent to a washing barrel during a washing process of the automatic putting-in washing machine is avoided and the user washing experience of the automatic putting-in washing machine is improved.