An operation control system comprising: a remote manipulator, being a remote control, including a transmitter that transmits a signal containing time information; and an operation control device that conducts wireless communication with the remote manipulator to perform vehicle operation control, the operation control device including: a clock; a receiver that receives the signal containing the time information from the remote manipulator; a calculator that calculates a delay time of the wireless communication, based on the time information and a time indicated by the clock; and a controller that, when the delay time is equal to or more than a threshold, changes the vehicle operation control from a normal control to a safety control, characterized in that the operation control device further includes an obstacle sensor that senses an obstacle in a surrounding area of a vehicle targeted for the vehicle operation control, and the operation control device performs the vehicle operation control in such a way that a sensing accuracy of the obstacle sensor under an operation control in the safety control is set to be higher than the sensing accuracy of the obstacle sensor in the normal control. a remote manipulator, being a remote control, including a transmitter that transmits a signal containing time information; and an operation control device that conducts wireless communication with the remote manipulator to perform vehicle operation control, the operation control device including: a clock; a receiver that receives the signal containing the time information from the remote manipulator; a calculator that calculates a delay time of the wireless communication, based on the time information and a time indicated by the clock; and a controller that, when the delay time is equal to or more than a threshold, changes the vehicle operation control from a normal control to a safety control, characterized in that the operation control device further includes an obstacle sensor that senses an obstacle in a surrounding area of a vehicle targeted for the vehicle operation control, and the operation control device performs the vehicle operation control in such a way that a sensing accuracy of the obstacle sensor under an operation control in the safety control is set to be higher than the sensing accuracy of the obstacle sensor in the normal control. a clock; a receiver that receives the signal containing the time information from the remote manipulator; a calculator that calculates a delay time of the wireless communication, based on the time information and a time indicated by the clock; and a controller that, when the delay time is equal to or more than a threshold, changes the vehicle operation control from a normal control to a safety control, characterized in that the operation control device further includes an obstacle sensor that senses an obstacle in a surrounding area of a vehicle targeted for the vehicle operation control, and the operation control device performs the vehicle operation control in such a way that a sensing accuracy of the obstacle sensor under an operation control in the safety control is set to be higher than the sensing accuracy of the obstacle sensor in the normal control.