To realize creation of a state in which two types of substances are communicated to each other via the double-ended needle assembly by a one-step continuous push operation and reduce a probability of entry of air or liquid leakage at that time. A syringe device 1 includes an administration holder 2, and a cylinder portion 6 which allows insertion of the administration holder 2. The cylinder portion 6 includes a coupling holder 3, a slit holder 4 coupled to the coupling holder 3, and a double-ended needle assembly 5 disposed slidably in an interior of the coupling holder 3. A cartridge for a freeze-dry product is mounted in the administration holder 2, and a cartridge for solvent is mounted in the coupling holder 3. When the administration holder 2 is pushed, the double-ended needle assembly 5 slides. When one of the needle points unseals the cartridge for freeze-dry product, the other needle point of the double-ended needle assembly 5 lightly prick the cartridge for the solvent, and the other needle point unseals the cartridge for solvent by a further sliding movement of the double-ended needle assembly 5.
