PURPOSE: To prevent the intrusion of foreign materials such as dust through an exhaust port of cooling air and the blocking of the exhaust port with mowed grass, etc., in an electric grass mower having a fan to cool a motor.

CONSTITUTION: The space in a motor case 3 containing a motor 9 mounted with a fan 12 is divided with partition walls 18a, 18b, 18c to form a cooling air suction channel 16 and a cooling air exhaustion channel 17 at both sides of the motor 9. A cooling air channel 5 connected with the cooling air suction channel 16 at one end and with outer atmosphere at the other end is formed in an operation lever 2 and the exhaust port 15 of the cooling air exhaustion channel 17 is opened downward toward the upper surface of a safety cover 14.