A wind shielding portion is provided in a front side of an exhaust port for cooling air from a motor such that it crosses over a lateral width with respect to a cutting direction. The cooling air which is blown to the wind shielding portion is effectively blown through a ventilation portion having a small ventilating resistance force and towards a marking line guide. Even when the cutting device main body is set at an incline, the cooling air is blown to the wind shielding portion, and is effectively blown through the ventilation portion to the marking line guide.