The present invention prevents foreign matter from infiltrating into a control valve and enables reduction in the cost of the valve. A strainer is mounted on an attachment portion of a valve sleeve, and a valve spool is disposed in the sleeve so as to be free to slidably advance and retreat. The strainer includes engagement portions m1 contacting first contact sites &egr;1 and &egr;2 formed on the attachment portion and a contact portion contacting second contact sites &egr;3 and &egr;4 formed on the attachment portion. Since the strainer includes the engagement portions m1 in contact with the first contact sites &egr;1 and &egr;2 and the contact portion in contact with the second contact sites &egr;3 and &egr;4, the sleeve has sufficient sealing contact with the strainer 73 at the first and second contact sites &egr;1 to &egr;4.