In this paper, we propose a MIP model for optimal planning of Countermaneuver Support Mission (CSM) through parallel machine scheduling. CSM is carried out by battle platoons of Engineer company, and is a military operation to stop or delay the enemy’s maneuver by using rockfall or bridge-blowing up. The concept of cooperation by platoons is proposed to shorten the mission completion time. We propose experimental results that the mission completion time with consideration of cooperation is shorter than that without consideration of cooperation. Additionally, we confirm that cooperation is still effective in shortening the mission completion time even if the capability is not at its maximum and is reduced by a certain ratio. Finally, since the parallel machine scheduling problem belongs to the NP-hard problem, we propose a solution approach using genetic algorithm in order to obtain a near optimal solution of a larger scale problem within a fast computation time.