Abstract: A multilevel processing in memory (PIM) includes a processor in which an optimal operator installed at several layers of memory, an accelerator type circuit for processing an irregular operation, and a scheduler for processing an irregular operation have been installed. The multilevel processing in memory includes a memory module including at least one rank in which a computation operation and a data storage operation are performed in response to a control command from a memory controller. The memory module, the rank, a PIM command scheduler included in the rank, a bank group processing unit, and a bank group constitute a plurality of layers, respectively.