Highly reliable vehicle system start controller

A vehicle system start controller comprising:

• an operation portion configured to be set to have a first state of operation when a vehicle system stops, and a second state of operation when said vehicle system operates;
• a first signal generation circuit operative in response to said operation portion being set to have said second state of operation to cause a first instruction signal to transition from a first logic state to a second logic state and thus output said first instruction signal, and maintain said first instruction signal in said second logic state until said operation portion is set to have the first state of operation;
• a second signal generation circuit outputting a second instruction signal depending on a state of operation of said operation portion, setting said second instruction signal to have said first logic state when said operation portion has said first state of operation, and setting said second instruction signal to have said second logic state when said operation portion has said second state of operation;
• a vehicle state detection portion detecting a state of a vehicle;
• and
• a decision circuit determining whether said operation portion has said first or second state of operation from a logic state of said first instruction signal for said first and second instruction signals having their respective logic states matching each other, and from whether a condition for speculating that said vehicle is parked is established in said state of said vehicle detected for said first and second instruction signals having a logic discrepancy therebetween.