PROBLEM TO BE SOLVED: To resolve a trouble wherein a working part resonances in according a vibration period of a traveling vibration of a machine body, a rise and down controlling vibration in a working part, an attitude controlling vibration of a balance elastic mast, etc., with a period of a natural vibration of the balance elastic part. SOLUTION: In this traveling working machine, an enforcing force controlling motor 17 controlling an enforcing force of a first balance elastic part 13 is provided in elastically supporting a planting work part 3 through right and left pair of balance elastic parts 13 and 14 and a resonance of the planting work part 3 is judged according to a detected signal of an operating pat inclining sensor 25 detecting a right or left inclining angle of the planting work part 3, then the enforcing force controlling motor 17 is automatically controlled in reciprocal driving according to the judgment of resonance.
