To make the easy replacement work of an indicator compatible with a compact production of a cylinder valve.

A handle is supported horizontally rotatably on the upper part of a housing 2 and an operation hole 21 extending vertically is provided in the housing 2 and an operation rod 22 is inserted in the operation hole 21. An upper support 43 and lower support 44 for supporting the indicator 31 near the operation hole 21 are provided on the housing 2 with the prescribed interval vertically. The inner diameter D of an upper hole 45 opened on the lower surface of the upper support 43 is formed bigger than the outer diameter (d) of the indicator 31 and a radius clearance R is formed between the outer periphery surface of the upper part of the indicator 31 and the upper hole 45. A push bolt 46 is screwed to the upper support 43 advancably/retreatably to the vertical direction and the indicator 31 is push-pressed to the lower support 44 by the push bolt 46.