To provide a working apparatus of a cylinder having structure enabling the other piston to be operated by reutilizing working fluid discharged when a piston is operated.

This cylinder working apparatus has a fixed-side member 10 provided with a working/placing part 11, a movable-side member 20 which is arranged oppositely to the fixed-side member and and in which a first cylinder part 21 provided with a first front-side inflow/outflow port 22 for the working fluid and a first rear-side inflow/outflow port 23 and a second cylinder part 25 provided with a second rear-side inflow/outflow port 26 for the working fluid and a second rear-side inflow/outflow port 27 connected with the first rear-side inflow/outflow port are formed, a connecting member 30 which is composed as a first piston part 32 one side of which is fixed to the fixed-side member as a fixing part 31 and the other side of which is inserted into the first cylinder part of the movable-side member and an operating member 40 which is provided with a second piston part 41 which is inserted into a second cylinder part of the movable-side member and the operating/pressurizing part 45 with which pressurization is performed to a material to be worked placed on the working/placing part of the fixed-side member.