An operation support device comprising: a manipulation input unit configured to output a manipulation command based on an input from an operator; and a motion unit configured to cause a surgical instrument to move based on the manipulation command, wherein the manipulation input unit includes an object-to-be-detected (3,3A, 3B) configured to be gripped by the operator, and a detection device (10, 10A) that detects the object-to-be-detected (3, 3A, 3B), wherein the object-to-be-detected (3, 3A, 3B) includes a body part that has first markers which are detected by the detection device (10, 10A), a manipulation part disposed in the body part and configured to be manipulated by the operator, and a second marker disposed in at least one of the body part and the manipulation part, wherein a state of the second marker changes in response to a manipulation on the manipulation part, wherein three first markers are provided which are arranged so that lengths of three sides of a triangle having the first markers as vertexes are different from each other, and so that a relative positional relationship of the first markers is fixed, the detection device (10, 10A) calculates a first information which is capable of specifying a position and an orientation of the object-to-be-detected (3, 3A, 3B) using at least the first markers and calculates a second information which is capable of specifying a manipulation input state to the manipulation part using at least the second marker, and wherein the manipulation input unit outputs a command for causing the surgical instrument to move as the manipulation command to the motion unit based on a result calculated by the detection device (10, 10B), thereby a motion of the surgical instrument is controlled based on the position and the orientation of the object-to-be-detected (3, 3A, 3B), and the manipulation input state. a manipulation input unit configured to output a manipulation command based on an input from an operator; and a motion unit configured to cause a surgical instrument to move based on the manipulation command, wherein the manipulation input unit includes an object-to-be-detected (3,3A, 3B) configured to be gripped by the operator, and a detection device (10, 10A) that detects the object-to-be-detected (3, 3A, 3B), an object-to-be-detected (3,3A, 3B) configured to be gripped by the operator, and a detection device (10, 10A) that detects the object-to-be-detected (3, 3A, 3B), wherein the object-to-be-detected (3, 3A, 3B) includes a body part that has first markers which are detected by the detection device (10, 10A), a manipulation part disposed in the body part and configured to be manipulated by the operator, and a second marker disposed in at least one of the body part and the manipulation part, wherein a state of the second marker changes in response to a manipulation on the manipulation part, a body part that has first markers which are detected by the detection device (10, 10A), a manipulation part disposed in the body part and configured to be manipulated by the operator, and a second marker disposed in at least one of the body part and the manipulation part, wherein a state of the second marker changes in response to a manipulation on the manipulation part, wherein three first markers are provided which are arranged so that lengths of three sides of a triangle having the first markers as vertexes are different from each other, and so that a relative positional relationship of the first markers is fixed, the detection device (10, 10A) calculates a first information which is capable of specifying a position and an orientation of the object-to-be-detected (3, 3A, 3B) using at least the first markers and calculates a second information which is capable of specifying a manipulation input state to the manipulation part using at least the second marker, and wherein the manipulation input unit outputs a command for causing the surgical instrument to move as the manipulation command to the motion unit based on a result calculated by the detection device (10, 10B), thereby a motion of the surgical instrument is controlled based on the position and the orientation of the object-to-be-detected (3, 3A, 3B), and the manipulation input state.