Poultry thigh slit processing device and poultry thigh automatic slit processing method

A poultry leg meat slit-forming device includes ankle holding part (2) that holds ankle of poultry leg meat (M), a blade unit (3) having slit-forming blade (23), an inserting driving part (4) that drives the blade unit (3), a leg meat pressing part (5) that presses surface of the poultry leg meat (M), and a moving part (9) that moves the ankle holding part (2), and the blade unit (3) includes a blade holding part (22) that holds a slit-forming blade (23) such that a blade edge of the slit-forming blade faces a side opposite with respect to the ankle holding part (2) in a direction of the slit-forming movement of the slit-forming blade (23) and that holds the slit-forming blade (23) so as to be displaceable in a front surface/back surface direction of the slit-forming blade, and a coil spring (25) that elastically biases the slit-forming blade (23) toward the bone of the poultry leg meat (M) in the front surface/back surface direction of the slit-forming blade (23).