Manufacturing method of conductive sheet and conductive sheet

A conductive sheet comprising:

• a support;
• conductive portions which are disposed on the support and contain metal silver and a resin binder;
• and
• resin binder portions each of which is present between the conductive portions,
• wherein each of the conductive portions has a lower layer not containing metal silver, an intermediate layer containing metal silver, and an upper layer not containing metal silver in this order,
• an average thickness of the upper layer is equal to or less than 0.40 μm, and
• a hydrophobization rate A determined by the following hydrophobization rate A-measuring method is equal to or greater than 90,
• (hydrophobization rate A-measuring method:
• 5 conductive sheets are prepared and dried for 24 hours at 110° C.;
• a mass X of each of the obtained conductive sheets is measured;
• the obtained conductive sheets are dipped into a sodium hypochlorite solution (25° C.) having an effective chlorine concentration of 5% for 10 minutes and then subjected to washing treatment (for 5 minutes) using water (20° C.);
• the obtained conductive sheets are dried for 24 hours at 110° C.;
• a mass Y of each of the obtained conductive sheets is measured;
• a hydrophobization rate A1 of each of the conductive sheets is calculated by using the following Equation (A);
• and the arithmetic mean of the values of the hydrophobization rate A1 of the 5 conductive sheets is calculated and taken as the hydrophobizing rate A, and in the Equation (A), a mass Z represents the mass of the support;
• Hydrophobization rate A1=[mass Y−mass Z]/[mass X−mass Z]×100). Equation (A):