To obtain an interchangeable lens which can be attached to a camera body and realize excellent photographing at plural focal distances by allowing a photographing propriety decision part to judge whether or not it is a photographing feasible range based on zoom position detecting information and to output photographing propriety information.

A CPU 9 detects a zoom position first. When zoom lens groups 6 and 7 move to a 1st or a 2nd focal distance position, the movable contact of the conductor brush of a zoom position detecting device 8 moves in contact with a fixed contact. Next, the CPU 9 judges whether or not the lens groups 6 and 7 are within the photographing feasible range. When the fixed contact is not short-circuited by the conductor brush, the CPU 9 judges that the lens groups 6 and 7 are within the photographing feasible range. When the fixed contact is short-circuited by the conductor brush, it judges that the lens groups 6 and 7 are not within the photographing feasible range. The CPU 9 outputs photographing feasible information when the lens groups 6 and 7 are within the photographing feasible range.