To provide a novel rotation mechanism having a smaller number of components or parts.A double-sided tape applicator in which a rotation mechanism is incorporated includes a case and a closure 200 rotated relative to the case. A spiral sloped surface 212 is formed on a side of the closure 200. The case has an abutted member 131 provided at an end of a push member 130. When a user pushes the push member 130 to abut or compress the abutted member 131 against the sloped surface 212, the closure 200 is rotated.