A method of transmit power control to allow a transmission side to execute transmit power control so that a signal to interference ratio (SIR) measured at a reception side is matched with a target SIR, the method includes digitizing a reception environment at the reception side, and setting the target SIR corresponding to an error rate of reception data for each of the reception environments; and changing the target SIR in accordance with the reception environment measured at the reception side or the reception environment selected at the reception side.