A vehicular engine starting system is provided in which a key cannot be removed from a key hole unless a shift lever is shifted to a parking position, the system including a pivot shaft having a cam surface that abuts against a blocking lever in response to movement of the pivot shaft from a LOCK position to an ACC position. The cam surface is formed into a shape that can move the blocking lever to an engaged position against a spring force of a return spring in response to movement of the pivot shaft from the ACC position toward an ON position. A plunger and the blocking lever are operatively connected so that the plunger is moved toward a retracted position in response to movement of the blocking lever from a disengaged position to the engaged position. Thus, the current consumption and heat generation of the solenoid can be suppressed in engaging the block lever with the pivot shaft in order to prevent the block lever from turning from the ACC position to the LOCK position.