We propose to use a helicopter for exploration of pit craters and caves on Mars. Helicopter does not contaminate inside of pit craters and caves because it does not emit gas including carbon compounds. In addition, a helicopter can explore caves even if the bottom of the caves is covered by rocks. We propose to explore the pit craters found near Elysium Mons because they are suitable for the aerial exploration because (1) there is higher possibility of existence of life and (2) air density is relatively high. We consider two specific missions using a helicopter; one is a mission which explores only a pit crater and the other is a mission which explores both a pit crater and a cave. The present analysis shows both missions are feasible.