A concrete vibrator, comprising: a vibrating tube including a motor and an eccentric weight ; ; a power supply unit configured to supply driving power to the motor a switch configured to perform switching between supply and supply stop of the driving power; a power supply cable configured to electrically connect the vibrating tube and the power supply unit to each other; and control means for controlling the driving power to the motor , characterized in that under control of the control means , the concrete vibrator is configured to operate in a normal mode in which the motor is supplied with driving power having a frequency that makes the motor rotate at a rotational speed suitable for an air bubble removing process, and in an idling mode in which the motor is supplied with driving power having a frequency that makes the motor rotate at a rotational speed lower than the rotational speed in the normal mode; while the motor is being driven, the control means measures, per unit of time, a value of a current that is input to the control means or the motor to record the measurement value in a memory, compares a latest current value input to the control means or the motor to a reference value calculated based on a past measurement value, to thereby calculate a comparison value, and further compares an absolute value of the comparison value to a threshold set in advance; in a case where the concrete vibrator is operated in the normal mode, when the absolute value of the comparison value falls below the threshold, a state where the absolute value of the comparison value falls below the threshold continues, and a continuous time of the state exceeds a reference time, an operation mode is changed to the idling mode; and in a case where the concrete vibrator is operated in the idling mode, when the absolute value of the comparison value exceeds the threshold, the operation mode is changed to the normal mode. a vibrating tube including a motor and an eccentric weight ; ; a power supply unit configured to supply driving power to the motor a switch configured to perform switching between supply and supply stop of the driving power; a power supply cable configured to electrically connect the vibrating tube and the power supply unit to each other; and control means for controlling the driving power to the motor , characterized in that under control of the control means , the concrete vibrator is configured to operate in a normal mode in which the motor is supplied with driving power having a frequency that makes the motor rotate at a rotational speed suitable for an air bubble removing process, and in an idling mode in which the motor is supplied with driving power having a frequency that makes the motor rotate at a rotational speed lower than the rotational speed in the normal mode; while the motor is being driven, the control means measures, per unit of time, a value of a current that is input to the control means or the motor to record the measurement value in a memory, compares a latest current value input to the control means or the motor to a reference value calculated based on a past measurement value, to thereby calculate a comparison value, and further compares an absolute value of the comparison value to a threshold set in advance; in a case where the concrete vibrator is operated in the normal mode, when the absolute value of the comparison value falls below the threshold, a state where the absolute value of the comparison value falls below the threshold continues, and a continuous time of the state exceeds a reference time, an operation mode is changed to the idling mode; and in a case where the concrete vibrator is operated in the idling mode, when the absolute value of the comparison value exceeds the threshold, the operation mode is changed to the normal mode. <EOS>