A compiler of this invention generates an object program 20 in which an area allocation instruction 11 to allocate an area for a structure of a list vector to be accessed in a loop and an area deallocation instruction 12 are converted into a new area allocation instruction 21 and a new area deallocation instruction 22, respectively. A new area allocation instruction processing unit 31 called by the new area allocation instruction 21 allocates an area 51 allocated in one operation of a size which is not less than an integral multiple of the size of an area for a structure, clips an area from the area 51, and assigns the area to the structure on a first area allocation request. The new area allocation instruction processing unit 31 clips an area contiguous to that for a previous structure from the area 51 allocated in one operation and assigns the area to a structure on second and subsequent calls. A new area deallocation instruction processing unit 32 called by the new area deallocation instruction 22 deallocates the whole of the area 51 allocated in one operation when it becomes unnecessary.