In executing debugging of an executable program in which a breakpoint is set at a conditional instruction using a software break technique, judgment of whether or not to stop the debugging is made, without use of a debugging device, in accordance with whether an execution condition expression of the conditional instruction is true or false. A processor capable of decoding and executing a program that includes conditional instructions executes debugging of the program. When a decoded instruction is a conditional break instruction (S201: YES, S202: YES), the processor identifies the type of the execution condition of the conditional break instruction (step S203), and refers to a status register to check a status flag of the execution condition (S204). If the execution condition is satisfied (S205: YES), the processor executes interrupt processing to suspend debugging (S206), and if the execution condition is not satisfied (S205: NO), the processor continues debugging.