An electrically assisted vehicle includes an electric motor, a device including a microcontroller and a transmission circuit that sends motor control-related data used to control rotation of the electric motor, and a control circuit that controls the electric motor based on the data. The control circuit and the device both retain the same data generation rule. When the control circuit sends first data to the device, the microcontroller generates second data which at least includes a portion of first reception data having been received, generates third data from the second data by using the rule, and sends, via the transmission circuit, the third data to the control circuit. The control circuit generates fourth data at least from the first data by using the rule, and compares a portion of second reception data received from the device against the fourth data. If the result of comparison indicates a match, the control circuit permits control of the electric motor.