A power tool comprising: a housing formed with an inlet hole (2a, 424a) and an exhaust hole; a brushless motor supported by the housing; a power supply circuit comprising at least one circuit element (92B, Q1-Q6) for supplying electric power of a power source to the brushless motor; a board on which the at least one circuit element (92B, Q1-Q6) is mounted; a board case accommodating therein the board; and a fan driven by rotation of the brushless motor to generate a cooling air flow flowing from the inlet hole (2a, 424a) to the exhaust hole in the housing, wherein the housing comprises a first housing, the first housing comprising a grip portion and supporting the brushless motor, wherein the brushless motor comprises a rotation shaft portion extending in a frontward/rearward direction, wherein the housing further comprises a motor case integrally molded in a hollow cylindrical shape extending in the frontward/rearward direction, the motor case supporting the brushless motor, wherein the motor case is formed with a communication hole allowing an interior of the first housing to be communicated with an interior of the motor case, wherein the inlet hole (2a, 424a) is formed in the first housing, wherein the at least one circuit element (92B, Q1-Q6) is disposed inside the first housing and is cooled by the cooling air flow, characterized in that the first housing further comprises a motor support portion supporting the motor case and having a rear wall portion facing the grip portion in the frontward/rearward direction, wherein a part of the board case is positioned between the motor case and the rear wall portion in the frontward/rearward direction, and that at least part of the inlet hole (2a, 424a) is positioned between the board case and the communication hole in the frontward/rearward direction. a housing formed with an inlet hole (2a, 424a) and an exhaust hole; a brushless motor supported by the housing; a power supply circuit comprising at least one circuit element (92B, Q1-Q6) for supplying electric power of a power source to the brushless motor; a board on which the at least one circuit element (92B, Q1-Q6) is mounted; a board case accommodating therein the board; and a fan driven by rotation of the brushless motor to generate a cooling air flow flowing from the inlet hole (2a, 424a) to the exhaust hole in the housing, wherein the housing comprises a first housing, the first housing comprising a grip portion and supporting the brushless motor, wherein the brushless motor comprises a rotation shaft portion extending in a frontward/rearward direction, wherein the housing further comprises a motor case integrally molded in a hollow cylindrical shape extending in the frontward/rearward direction, the motor case supporting the brushless motor, wherein the motor case is formed with a communication hole allowing an interior of the first housing to be communicated with an interior of the motor case, wherein the inlet hole (2a, 424a) is formed in the first housing, wherein the at least one circuit element (92B, Q1-Q6) is disposed inside the first housing and is cooled by the cooling air flow, characterized in that the first housing further comprises a motor support portion supporting the motor case and having a rear wall portion facing the grip portion in the frontward/rearward direction, wherein a part of the board case is positioned between the motor case and the rear wall portion in the frontward/rearward direction, and that at least part of the inlet hole (2a, 424a) is positioned between the board case and the communication hole in the frontward/rearward direction.