The new service of Korean public library, ASK_a service model suggests a new management practice in collaborative digital reference services. The model has three functions: input transaction, process transaction, and output transaction. The best form for input is the web form. The best form for process is a model with a hybrid type of public libraries(hierarchical and lateral type). The output suggests the archiving policy for gathering the query-answer data. The core of this model is providing an advanced information service to its users through cooperation with public libraries and external manpower.