A portable electric cutter having a motor, the portable electric cutter comprising: a housing in which the motor is accommodated; a saw blade driven to rotate by the motor; a base coupled to the housing, having a bottom surface slidable on a material to be cut, and having an opening through which the saw blade can protrude downward from the bottom surface; a fan driven to rotate by the motor and cooling the motor by fan air generated by the rotation, wherein the fan is accommodated in a motor casing in the housing together with the motor; a driving circuit including switching elements (Q1-6) for switching power supplied to the motor; a control circuit for controlling the driving circuit; a circuit board on which one or both of the driving circuit and the control circuit is mounted, wherein an inside of the housing in which the circuit board is accommodated communicates with the motor casing, and motor cooling air vents provided in the housing on a side opposite to the saw blade, wherein the motor is a brushless motor, a rotation state detection unit for generating a signal in accordance with a rotation position of the motor is further provided, and the control circuit receives the signal of the rotation state detection unit and transmits a signal for controlling the drive of the motor to the driving circuit, characterized in that circuit board cooling air vents (66, 67) are provided in a side surface of the housing, wherein the circuit board is disposed between the circuit board cooling air vents (66, 67), which are provided in the housing, and the motor casing, wherein, the circuit board is disposed in a circuit board casing in the housing and the circuit board casing is located at a position between a handle of the housing and the base, wherein a space, which communicates between the motor casing and the circuit board casing, is provided in the housing andserves as an air flow path; and at least a part of the circuit board is disposed on a radially outer side of the fan when a direction orthogonal to a rotation axis of the fan is defined as a radial direction, at least a part of the circuit board being disposed in a flow path of the fan air. a housing in which the motor is accommodated; a saw blade driven to rotate by the motor; a base coupled to the housing, having a bottom surface slidable on a material to be cut, and having an opening through which the saw blade can protrude downward from the bottom surface; a fan driven to rotate by the motor and cooling the motor by fan air generated by the rotation, wherein the fan is accommodated in a motor casing in the housing together with the motor; a driving circuit including switching elements (Q1-6) for switching power supplied to the motor; a control circuit for controlling the driving circuit; a circuit board on which one or both of the driving circuit and the control circuit is mounted, wherein an inside of the housing in which the circuit board is accommodated communicates with the motor casing, and motor cooling air vents provided in the housing on a side opposite to the saw blade, wherein the motor is a brushless motor, a rotation state detection unit for generating a signal in accordance with a rotation position of the motor is further provided, and the control circuit receives the signal of the rotation state detection unit and transmits a signal for controlling the drive of the motor to the driving circuit, characterized in that circuit board cooling air vents (66, 67) are provided in a side surface of the housing, wherein the circuit board is disposed between the circuit board cooling air vents (66, 67), which are provided in the housing, and the motor casing, wherein, the circuit board is disposed in a circuit board casing in the housing and the circuit board casing is located at a position between a handle of the housing and the base, wherein a space, which communicates between the motor casing and the circuit board casing, is provided in the housing andserves as an air flow path; and at least a part of the circuit board is disposed on a radially outer side of the fan when a direction orthogonal to a rotation axis of the fan is defined as a radial direction, at least a part of the circuit board being disposed in a flow path of the fan air.