A bonding method using a bonding agent is provided, which has the steps of forming an underlayer on a first member, providing a bonding agent on the underlayer, forming a contact member, different from the bonding agent, on a second member, bringing the bonding agent into contact with the contact member so that the first member and the second member are bonded to each other. In the method described above, the wettability of the bonding agent to the underlayer is superior to that of the bonding agent to a surface of the first member before the underlayer is formed thereon, and the bondability of the bonding agent to the contact member is superior to that of the bonding agent to a surface of the second member before the contact member is formed thereon.