To provide a filter device which allows the exchange of a filter without the need for touching the filter wet with a processing liquid with hands at all and allows the release of the filter from a main body section by one operation.

This filter device has the main body section 2 and a filter section 3 for filtering the processing liquid. The main body section 2 is provided with a pin guide section 4 and a detaining part 41a. A release pin 10 for pressing the filter section 3 by moving into and out of the main body section 2 is mounted at this pin guide section 4. A part 14a to be detained which is disposed at the filter section 3 is detained with the detaining part 41a. When the release pin 10 is projected from the main body section 2 to press the filter section 3, the detaining state of the part 14a to be detained of the filter section 3 to the detaining section 41a of the main body section 2 is released and the filter section 3 is separated from the main body section 2 without touching the filter section 3 with the hands at all.