An apparatus and method for detecting software error are provided. Trace files are respectively generated by a target machine and a functional simulator that imitates the target machine and performs the same operation as the target machine. Each of the trace files may include at least one of a data-flow-type trace including execution information about one or more instructions and a control-flow-type trace representing information about a part in which a change in address indicating the position of an instruction is a predetermined threshold value or more when the instruction is executed. By comparing the generated trace files, software error may be detected.