A micro-manipulator has grippers for gripping micro-material; an actuator
for driving the grippers; a drive amount detection device for detecting a
drive amount of the actuator; a power control device for controlling
power supplied to the actuator so that a difference in a target drive
amount of the input actuator and a drive amount detected by the drive
amount detection device is small, after at least the grippers touch the
micro-material; a gripping determination device for determining that
grippers have gripped the micro-material based on the difference; and a
resilience value calculation device for calculating a resilience value
that represents a degree of softness of the micro-material by dividing
the actuator drive force that is equivalent to the repulsive force of
micro-material gripped by the grippers in proportion to power supplied to
the actuator via the power control device.