A log acquisition method is provided that allows a processing log of software to readily be acquired and reduces the man-hours needed for analyzing a bug. The method for acquiring a runtime log of a program including at least one function for performing a predetermined process, comprising changing the address of said at least one function to the address of a function for log acquisition, wherein said function for log acquisition comprises: calling said at least one function to cause said predetermined process to be executed, receiving the result of the execution and passing said result to said program; determining whether or not a pointer parameter the type of which is specified in a predetermined manner is defined in a function definition in said program; if yes, recording a memory content pointed to by said pointer parameter as data of the specified data type. The type of the pointer parameter may defined by an index structure, and the determining step includes judging the type of the pointer parameter by referring to the specified member of the index structure. The types of the members of the index structure may be various kinds of unexported functions and various kinds of structures and etc.