A power tool comprising: a brushless motor including a rotation shaft; a fan provided coaxially with the rotation shaft and rotating in synchronism with the brushless motor; switching elements that drive the brushless motor; an inverter circuit board on which the switching elements are mounted; a transmission portion that transmits a driving force of the brushless motor; and a housing that houses the brushless motor and the fan, the switching elements, the inverter circuit board and the transmission portion therein, wherein the rotation shaft is rotatably held by a first bearing provided near a center portion of a body portion of the housing and a second bearing on a rear end side of the body portion; wherein the switching elements include semiconductor elements each having terminals (5d, 5e) on a bottom surface plane thereof, and wherein the switching elements are surface mounted on the inverter circuit board, which is positioned so as to be oriented in a vertical direction with respect to the axial direction of the rotation shaft, wherein exhaust slits (18a-d) are formed at a portion of the housing at the periphery of the fan and suction slits are formed in the body portion of the housing at an outer peripheral side of the inverter circuit board on the rear side of the brushless motor, characterised in that the fan is attached between the rotor of the brushless motor and the first bearing, the fan is provided on the front side of the brushless motor in the axial direction of the rotation shaft, and the inverter circuit board is provided on a rear surface side of the brushless motor in the axial direction of the rotation shaft, and the switching elements are arranged such that their longitudinal directions are parallel to the inverter circuit board and their bottom surfaces are opposed to the inverter circuit board. a brushless motor including a rotation shaft; a fan provided coaxially with the rotation shaft and rotating in synchronism with the brushless motor; switching elements that drive the brushless motor; an inverter circuit board on which the switching elements are mounted; a transmission portion that transmits a driving force of the brushless motor; and a housing that houses the brushless motor and the fan, the switching elements, the inverter circuit board and the transmission portion therein, wherein the rotation shaft is rotatably held by a first bearing provided near a center portion of a body portion of the housing and a second bearing on a rear end side of the body portion; wherein the switching elements include semiconductor elements each having terminals (5d, 5e) on a bottom surface plane thereof, and wherein the switching elements are surface mounted on the inverter circuit board, which is positioned so as to be oriented in a vertical direction with respect to the axial direction of the rotation shaft, wherein exhaust slits (18a-d) are formed at a portion of the housing at the periphery of the fan and suction slits are formed in the body portion of the housing at an outer peripheral side of the inverter circuit board on the rear side of the brushless motor, characterised in that the fan is attached between the rotor of the brushless motor and the first bearing, the fan is provided on the front side of the brushless motor in the axial direction of the rotation shaft, and the inverter circuit board is provided on a rear surface side of the brushless motor in the axial direction of the rotation shaft, and the switching elements are arranged such that their longitudinal directions are parallel to the inverter circuit board and their bottom surfaces are opposed to the inverter circuit board.