A portable timepiece has a pipe extending from a case and a winding stem for transmitting a rotational force to a timepiece movement in the case. A crown is connected to the winding stem for rotational movement therewith and for detachable engagement with an outer periphery of a male threaded section of the pipe to prevent unintentional rotation of the crown. The crown has a crown shaft for rotating the winding stem, a crown head having a female threaded section for threaded engagement with the male threaded section and mounted for undergoing rotation to rotate the crown shaft in a state in which the engagement between the male and female screw sections is released. A clutch couples together the crown shaft and the crown head to prevent rotation of the crown shaft in a state in which the male and female threaded sections are engaged with one another and couples the crown shaft and the crown head to allow the crown shaft to rotate during rotation of the crown head in a state in which the male and female threaded sections are not engaged with one another.