A step apparatus for heavy construction equipment and treeharvester comprises a step protector including a cylinderfixing holder formed inside a protector housing a first stepframe including a first lug support flange coupled to the firstfixing lug a second step frame including a second lug supportflange coupled to the second fixing lug, a plurality of stepsupport flanges formed apart from the second lug supportflange, and a fixing cam formed adjacent to the second lugsupport flange to support a rotating force generated about arotating shaft formed on the second lug support flange footsteps fixed to the plurality of step support flanges formed inthe first step frame and the second step frame, respectivelyand a folding actuator providing the rotating force to thefixing cam by a predetermined pressure.
