To inform ink leakage to a user, to prevent a head failure due to the leakage and to improve reliability by measuring current flowing by applying voltage to a pad of a recording head, and sensing the leakage in response to a measured result.

A pad part has a VH electrode, GNDH electrode 22 and 15 signal pads 23. VH electrode 21 and electrodes 22 are disposed to surround the pads 23. In the case of applying voltage to the electrode 21 due to ink leakage from the pad part, flowing leakage current is several to several tens mA immediately after the VH voltage is applied in the state that the part is moistened with the ink. It is gradually decreased as time goes, and finally reduced to substantially '0'. The ink leaked from a discharge port 1 moistens the electrode 21 surrounding the circumference and the GNDH 22 to a signal pad part.