A work object processing apparatus includes a memory unit configured to include a user memory region associated with user information, a message thread memory region accessible through the user information and associated with a message thread, and a work object memory region accessible through the message thread and associated with a work object, a message thread processing unit configured to receive a work object, including a work producer, a work processor, and work contents, through a chat room associated with a message thread and to process work object operation on the message thread, and a work object processing unit configured to process a work object state of the work object changed in a work processing diagram depending on a work interaction between the work producer and the work processor.