A work machine unit includes: a support member assembled to an end effector connection part of an operating machine; a work machine part assembled to one end of the support member; and a linear guide disposed at another end of the support member across its connection to the end effector connection part from the support member, arranged in parallel to an axial direction of the work machine part, and configured to abut against a work object or its peripheral structural object. Further, the linear guide is passed through a through-hole formed in the support member, and the support member is configured to move in the axial direction of the work machine part as guided by the linear guide.