The robot simulation apparatus includes: a workpiece model setting unit 11 that sets a workpiece model; a posture condition setting unit 16 that sets a condition related to a posture taken by the workpiece model, as a posture condition, when the workpiece model set by the workpiece model setting unit 11 is disposed in a virtual work space as a virtually formed work space; a bulk pile data generating unit 20 that generates bulk pile data of the plurality of workpiece models piled up in the virtual work space, in accordance with the posture condition set by the posture condition setting unit 16; and a picking motion simulating unit 30 that executes a picking motion simulation for verifying the picking motion of the workpiece models in the virtual work space, with respect to the bulk pile data generated by the bulk pile data generating unit 20.