1. A method of compiling a source program into an object program comprising the steps of: converting said source program on a predetermined unit basis into an intermediate code; correlating said converted intermediate codes with said source program to be compiled and managing information representing the correlation; intercepting a compiling operation when an error is detected; if the compiling operation is again executed after said error is corrected, determining the range of said source program correctly compiled, in accordance with said information; resuming the compiling operation of said source program immediately after said range of said source program correctly compiled; and converting said generated intermediate code to the object program.