An elastic support device, comprising: a first member including a first magnet; and a second member including a second magnet and disposed so as to face the first member, the second member being movable relative to the first member in response to receipt of an external force, wherein a magnetic force acting between the first magnet and the second magnet holds the second member in an original position when the second member does not receive an external force, and the magnetic force returns the second member to the original position when the second member is moved due to receipt of an external force, wherein a first magnetic pole of the first magnet is disposed so as to face toward the second member, and each of the first magnet and the second magnet includes a plurality of magnets arranged at intervals along a moving direction of the second member, characterized in that the first magnetic pole of the second magnet is disposed so as to face toward the first member, and a repulsive force acting between the first member and the second member is balanced when the second member is in the original position, and the repulsive force acts between the first member and the second member so as to return the second member to the original position when the second member is moved due to an external force acting on the second member, each of the plurality of magnets of the first magnet is disposed at an intermediate position between the plurality of magnets of the second magnet along the moving direction of the second member in the original position, and the second member is integrally provided with a support target part to which a knife as an attachment part is attached. a first member including a first magnet; and a second member including a second magnet and disposed so as to face the first member, the second member being movable relative to the first member in response to receipt of an external force, wherein a magnetic force acting between the first magnet and the second magnet holds the second member in an original position when the second member does not receive an external force, and the magnetic force returns the second member to the original position when the second member is moved due to receipt of an external force, wherein a first magnetic pole of the first magnet is disposed so as to face toward the second member, and each of the first magnet and the second magnet includes a plurality of magnets arranged at intervals along a moving direction of the second member, characterized in that the first magnetic pole of the second magnet is disposed so as to face toward the first member, and a repulsive force acting between the first member and the second member is balanced when the second member is in the original position, and the repulsive force acts between the first member and the second member so as to return the second member to the original position when the second member is moved due to an external force acting on the second member, each of the plurality of magnets of the first magnet is disposed at an intermediate position between the plurality of magnets of the second magnet along the moving direction of the second member in the original position, and the second member is integrally provided with a support target part to which a knife as an attachment part is attached.