To provide an on-vehicle start control device capable of easily moving a vehicle even when a starting switch of a prime mover such as an engine breaks down.

The on-vehicle start control device, which has an IG switch 1 and ST switch 2 for starting an engine 16 for driving the vehicle, and starts the engine 16 by a switch operation in a given order, includes: a normal operation detection part 6 that detects the switch operation of IG switch 1 and ST switch 2; an order determination part 7 that determines the order of the detected switch operation; a start limiting part 8 that limits the start of engine 16 when it is determined that the switch operation is not performed in the given order; an emergency control detection part 4 that detects a preset emergency control; and a start permission part 5 that permits the start of engine 16 when the emergency control is detected in the state where the start of engine 16 is restricted.