Transfer device and image forming apparatus

A transfer device according to the present invention have a current detector for detecting a value of an upstream current flowing from an intermediate transfer belt into a tension roller, a transfer bias power source for performing control in such a manner as to prevent any further increase in output voltage value even if an output current value becomes lower than a value which should be subjected to a constant-current control in the case where an output signal from the current detector is a signal indicating 3.2 muA. Consequently, it is possible to suppress the unclearness of the edge of a transfer image caused by the upstream current flowing in a visible image carrying belt upstream of a transfer position such as a nip.