To supply in direct to an electric tool the electric power from a portable large capacity storage battery with the power supply repeater body which is similar in the shape to a charger of the related art to assure the use of long term, without frequent replacement of a charging battery unlike the related art and without modification or the like to the charging battery connection structure of an electric tool.

A power supply repeater 1 which may be loaded to be removable to the power supply part T1 in an electric tool T using the predetermined portable charger as the power supply is formed. This power supply repeater 1 is provided with an input terminal 3 to input the power from a storage battery B via an input line 2, and an output terminal 4 to supply the power to the electric tool T. Moreover, the power supply repeater 1 is provided with a charging means having a charging battery structure, and a charging change-over switch for changing over the supply of power to a charging means from the input terminal 3 or for changing over the supply of power to the output terminal 4 from the input terminal 3. Moreover, the power supply repeater 1 is also used to charge the storage battery B through connection wit the charger for charging the charging battery.