A lock mechanism with state indication function, comprising a housing , a cap and an indicator , the cap having a central axis and being mounted for rotational movement relative to the housing about the central axis between a latched position and an unlatched position, the cap comprising a radial convex portion which extends radially and rotates along with the cap about the central axis ; the indicator being interposed between the cap and the housing , and comprising an indicating portion which is in covering relationship to the cap , the indicator being pivotally mounted on the housing about a projection , the indicator moving radially and outwardly with respect to the cap from the central axis when the cap rotates from the latched position to the unlatched position, making the indicating portion of the indicator no longer in covering relationship to the cap ; wherein the indicator comprises an active indicator arranged circumferentially around the central axis , the active indicator comprises a cam matching surface (3a-1) extending circumferentially around the central axis and a stopping end (3a-2) located at an end of the cam matching surface (3a-1) corresponding to the pivoting center of the active indicator ; the radial convex portion slides along the cam matching surface (3a-1) to make the active indicator rotate about the projection to move away from the central axis of the cap ; the radial convex portion pushes the stopping end (3a-2) of the active indicator to make the active indicator rotate about the projection to a recovery position in which the indicating portion is covered by the cap ; and characterized in that , the indicator further comprises a passive indicator arranged circumferentially around the central axis , the passive indicator is linked with the active indicator through a gear transmission device, making the passive indicator be unfolded and folded synchronously along with the active indicator . the cap having a central axis and being mounted for rotational movement relative to the housing about the central axis between a latched position and an unlatched position, the cap comprising a radial convex portion which extends radially and rotates along with the cap about the central axis ; the indicator being interposed between the cap and the housing , and comprising an indicating portion which is in covering relationship to the cap , the indicator being pivotally mounted on the housing about a projection , the indicator moving radially and outwardly with respect to the cap from the central axis when the cap rotates from the latched position to the unlatched position, making the indicating portion of the indicator no longer in covering relationship to the cap ; wherein the indicator comprises an active indicator arranged circumferentially around the central axis , the active indicator comprises a cam matching surface (3a-1) extending circumferentially around the central axis and a stopping end (3a-2) located at an end of the cam matching surface (3a-1) corresponding to the pivoting center of the active indicator ; the radial convex portion slides along the cam matching surface (3a-1) to make the active indicator rotate about the projection to move away from the central axis of the cap ; the radial convex portion pushes the stopping end (3a-2) of the active indicator to make the active indicator rotate about the projection to a recovery position in which the indicating portion is covered by the cap ; and characterized in that , the indicator further comprises a passive indicator arranged circumferentially around the central axis , the passive indicator is linked with the active indicator through a gear transmission device, making the passive indicator be unfolded and folded synchronously along with the active indicator . <EOS>