An operation support device (100; 120; 130; 140; 150; 160) having a surgical instrument unit (1; 21; 61) and a surgical instrument unit support section configured to detachably support the surgical instrument unit (1; 21; 61), the operation support device (100; 120; 130; 140; 150; 160) comprising: a sterilizable intermediate member (2; 22; 42, 43; 72) configured to detachably hold the surgical instrument unit (1; 21; 61) by a shaft-shaped section (1B; 21C) of the surgical instrument unit (1; 21; 61) being inserted into the intermediate member (2; 22; 42, 43; 72) and passing through a surgical instrument unit insertion hole (2d; 22d); a sterilizable shielding member (7, 6A, 6B, 6C, 6D; 7, 56) having at least two hole portions (7C, 7D) engaged with the intermediate member (2; 22; 42, 43; 72); a driving force supply unit (3; 23; 53; 63; 73) installed at the surgical instrument unit support section, configured to detachably hold the intermediate member (2; 22; 42, 43; 72) by the intermediate member (2; 22; 42, 43; 72) being inserted into a through-hole portion (3d; 23d) of the driving force supply unit (3; 23; 53; 63; 73), and configured to supply a driving force to the surgical instrument unit (1; 21; 61) via the intermediate member (2; 22; 42, 43; 72); and a first space (A U) and a second space (A C) formed by inserting the intermediate member (2; 22; 42, 43; 72) into one of the hole portions (7C, 7D) of the shielding member (7, 6A, 6B, 6C, 6D; 7, 56), inserting the intermediate member (2; 22; 42, 43; 72) into the driving force supply unit (3; 23; 53; 63; 73), and inserting the intermediate member into another of the hole portions (7C, 7D) of the shielding member (7, 6A, 6B, 6C, 6D; 7, 56), wherein the driving force supply unit (3; 23; 53; 63; 73) and the surgical instrument unit support section are disposed in the first space (A U), in the second space (A C), the intermediate member (2; 22; 42, 43; 72) holds the surgical instrument unit (1; 21; 61) by the surgical instrument unit (1; 21; 61) being inserted into the intermediate member (2; 22; 42, 43; 72), and the driving force supply unit (3; 23; 53; 63; 73) rotates the surgical instrument unit (1; 21; 61) about a longitudinal axis (O 1, O 2, O 3,O 21, O 22, O 23) by rotating the intermediate member about the longitudinal axis (O 1, O 2, O 3, O 21, O 22, O 23). a sterilizable intermediate member (2; 22; 42, 43; 72) configured to detachably hold the surgical instrument unit (1; 21; 61) by a shaft-shaped section (1B; 21C) of the surgical instrument unit (1; 21; 61) being inserted into the intermediate member (2; 22; 42, 43; 72) and passing through a surgical instrument unit insertion hole (2d; 22d); a sterilizable shielding member (7, 6A, 6B, 6C, 6D; 7, 56) having at least two hole portions (7C, 7D) engaged with the intermediate member (2; 22; 42, 43; 72); a driving force supply unit (3; 23; 53; 63; 73) installed at the surgical instrument unit support section, configured to detachably hold the intermediate member (2; 22; 42, 43; 72) by the intermediate member (2; 22; 42, 43; 72) being inserted into a through-hole portion (3d; 23d) of the driving force supply unit (3; 23; 53; 63; 73), and configured to supply a driving force to the surgical instrument unit (1; 21; 61) via the intermediate member (2; 22; 42, 43; 72); and a first space (A U) and a second space (A C) formed by inserting the intermediate member (2; 22; 42, 43; 72) into one of the hole portions (7C, 7D) of the shielding member (7, 6A, 6B, 6C, 6D; 7, 56), inserting the intermediate member (2; 22; 42, 43; 72) into the driving force supply unit (3; 23; 53; 63; 73), and inserting the intermediate member into another of the hole portions (7C, 7D) of the shielding member (7, 6A, 6B, 6C, 6D; 7, 56), wherein the driving force supply unit (3; 23; 53; 63; 73) and the surgical instrument unit support section are disposed in the first space (A U), in the second space (A C), the intermediate member (2; 22; 42, 43; 72) holds the surgical instrument unit (1; 21; 61) by the surgical instrument unit (1; 21; 61) being inserted into the intermediate member (2; 22; 42, 43; 72), and the driving force supply unit (3; 23; 53; 63; 73) rotates the surgical instrument unit (1; 21; 61) about a longitudinal axis (O 1, O 2, O 3,O 21, O 22, O 23) by rotating the intermediate member about the longitudinal axis (O 1, O 2, O 3, O 21, O 22, O 23).