PURPOSE: To surely prevent a cartridge chamber cover from being opened when film is being pulled out from a cartridge case and to prevent a camera from getting large and the cost from getting high by linking a cartridge chamber over locking mechanism with a light shading door opening/closing mechanism without using a complicated mechanism in a device using a thrust type cartridge provided with a light shading door at a film inserting port.

CONSTITUTION: A holding recessed part 10d recessed in a direction crossed with the opening/closing direction of the cartridge chamber cover 11 is formed in a camera main body 10; and an engaging member 19 consisting of 1st engaging parts 19a and 19b engaged with one side end 5b of a linking member and a 2nd engaging part 19c engaged with and disengaged from the recessed part 10d of the camera main body 10 is provided in the cover 11. The 2nd engaging part 19c is engaged with the recessed part 10d in a state where the light shading door is opened, and it is disengaged from the recessed part 10d in a state where the door is closed. Then, a light shading door opening/closing member 18 is engaged with the other side end 5a of the linking member.