Cylinder roundness correcting and keeping device

A cylinder roundness correcting and keeping device relates to an improvement on a structure of a cylinder roundness adjusting and keeping device. The utility model provides a cylinder roundness correcting and keeping device with the advantages of convenient use, convenient disassembly, stable quality and higher efficiency. The device includes a center plate and has structural points as follows: the center plate is taken as the center, support rods are evenly distributed outwards, arc plates are arranged on connecting sleeves of end heads of adjusting bolts of the support plates, the adjusting bolts of the support plate are arranged on two sides of the support rods, and the arc plates are fixed in guide grooves at the end heads of the support rods through positioning places, positioning bolts and positioning nuts.