In order to improve the efficiency in development of RTOS-mounted application, there is to provide a compiler of creating executable code for running application of calling and using the resource of the RTOS as object on a target device, including an RTOS setting information optimization unit of receiving system configuration information and a compile unit of receiving application source code. The RTOS setting information optimization unit creates RTOS resource creating information including attribute information of usable objects, based on the system configuration information. The compile unit creates the RTOS setting information including a list of the objects actually used, from the analysis result of the RTOS resource creating information and the application source code and the RTOS setting information optimization unit optimizes the above based on the system configuration information.