A robot hand apparatus (1) includes a base (2); a motor (M); a first-link (10) supported by the base (2) while allowing the rotation around a first axis (S1), which is in parallel to an actuation axis (G) of the motor (M) and is positioned apart from the actuation axis (G), the first-link (10) has a first guide path (11b) movably supporting a control axis (42); a second link (20) which connects with the actuation axis (G) and supports the control axis (42), and moves the control axis (42) within the first guide path (11b) in accordance with the rotation of the actuation axis (G); and a finger link (F1) supported by the first link (10) while allowing the rotation around a second axis; and the finger link (F1) directly or indirectly links with the control axis (42) and is rotated by the actuation of the control axis (42).