To provide a liquid flow path on-off valve capable of reliably switching opening/closing of a liquid flow path through simple operation.

The liquid flow path on-off valve includes: a valve element 82 for opening/closing a communication hole 81d; an operating button 83 which is depressed to move the valve element 82; and a compression spring 82e which energizes the operating button 83 oppositely to a depression direction and energizes the valve element 82 in the direction to close the communication hole 81d. The operating button 83 includes an endless cam groove 85 in which a plurality of slopes and steps which are inclined upward to one side of a circumferential direction are formed on a groove bottom. A valve body 81 includes an engage pin 86 of which the distal end is engaged with the cam groove 85 and each time the operating button 83 is depressed, opening/closing of the communication hole 81d by the valve element 82 is switched.