Pressure measuring device and medical device

A pressure measuring device to and from which a detaching-attaching member including a fluid flow channel in which a fluid is flowable is attached and detached and which measures pressure in a measurement target which is the attaching-detaching member, the pressure measuring device comprising:

• a communication flow channel placed to allow communication of gas with the fluid flow channel;
• a connection portion to which a connection counterpart portion of the attaching-detaching member is connected to bring the fluid flow channel and the communication flow channel to a communication state or a non-communication state;
• a pressure sensor that measures pressure in the fluid flow channel and the communication flow channel in a case where the connection counterpart portion is connected to the connection portion to bring the fluid flow channel and the communication flow channel in the communication state;
• a pressure increasing-decreasing unit that increases or decreases pressure in the communication flow channel to discharge or suction gas outside;
• and
• a driving unit that causes the pressure increasing-decreasing unit to be driven manually or automatically at a timing at which a first contact surface of the connection portion to be brought into airtight contact with the connection counterpart portion is away from the connection counterpart portion, wherein
• the first contact surface of the connection portion is formed at a location where gas is discharged or a location where gas is suctioned by the pressure increasing-decreasing unit increasing or decreasing the pressure in the non-communication state where the connection portion is away from the connection counterpart portion.