The experiment was conducted to reduce the labor and production cost with the labor save of harvest in cultivating the onion using the machine and the results are as follows. On labor saving effect in transparent vinyl mulching, digging working hours per 10a in the case of using tractor are 55 min., fixing + turning time is 11 min.,the time of harvest is 66 min, digging working hours using cultivator are 90 min. and fixing + turning time is 9 min., but the time of hand harvesting is 693 min and 41 sec. and in digging labor saving effect, tractor shows 90% in the harvesting period and harvest by cultivator 86%. On nonmulching cases, the harvest by tractor takes 44 min. and that by cultivator does 75 min, and digging labor saving effect shows 93.6% in the tractor harvest and 89% in the cultivator harvest. Therefore, on the operation efficiency per hour, in the case of tractor with digger vinyl mulching and nonmulching show $0.091sim0.136ha$ and in the case of cultivator with digger-both show $0.061sim0.08ha$, but in the case of hand harvest, vinyl mulching and nonmulching are $0.008sim0.009ha$, so in the mechanized harvest of onion, the harvest by tractor with digger is the best. On the cost and labor save for harvesting the onion with labor saving effect, tractor shows 19 hours and 26min./10a in vinyl mulching and 18 hours and 54min./10a in nonmulching, so it shows the short hours for harvesting. And labor saving effect shows 37% in comparison with 29 hours and 49 min. $sim30$ hours and 38 min.($110,587sim113,925won$) of the hand harvest, so the cost was reduced to $69,525sim72,225won$. On the cultivator with diggers, vinyl mulching takes 19 hours and 49 min and nonmulching 20 hours and 2 min., so the labor saving effect and cost were reduced to $32sim36%$($73,087sim75,075$ won) in comparison with the hand harvest.