An electric power tool comprising: a main body including a motor, a controller, a battery authentication information holding unit, and a main body identification information holding unit, wherein the battery authentication information holding unit is configured to hold battery authentication information, and the main body identification information holding unit is configured to hold main body identification information; and a battery pack including a main body identification information acquisition unit, a battery identification information holding unit, a main body authentication information holding unit, and a main body authentication unit, wherein the battery identification information holding unit is configured to hold battery identification information, and the main body authentication information holding unit is configured to hold main body authentication information, the electric power tool characterized in that the main body identification information acquisition unit is configured to acquire the main body identification information of the main body identification information holding unit from the main body, the main body authentication unit is configured to authenticate the main body based on the main body authentication information held by the main body authentication information holding unit and the main body identification information, and the controller is configured to acquire the battery identification information of the battery identification information holding unit in accordance with a battery authentication program, the controller is configured to authenticate the battery pack based on the battery identification information and the battery authentication information held by the battery authentication information holding unit, and the controller is configured to control and drive the motor based on the authentication result of the battery pack and the authentication result of the main body authentication unit. a main body including a motor, a controller, a battery authentication information holding unit, and a main body identification information holding unit, wherein the battery authentication information holding unit is configured to hold battery authentication information, and the main body identification information holding unit is configured to hold main body identification information; and a battery pack including a main body identification information acquisition unit, a battery identification information holding unit, a main body authentication information holding unit, and a main body authentication unit, wherein the battery identification information holding unit is configured to hold battery identification information, and the main body authentication information holding unit is configured to hold main body authentication information, the electric power tool characterized in that the main body identification information acquisition unit is configured to acquire the main body identification information of the main body identification information holding unit from the main body, the main body authentication unit is configured to authenticate the main body based on the main body authentication information held by the main body authentication information holding unit and the main body identification information, and the controller is configured to acquire the battery identification information of the battery identification information holding unit in accordance with a battery authentication program, the controller is configured to authenticate the battery pack based on the battery identification information and the battery authentication information held by the battery authentication information holding unit, and the controller is configured to control and drive the motor based on the authentication result of the battery pack and the authentication result of the main body authentication unit.