To make spaces between cells narrow in a planar array type fuel battery with cells arrayed in plane.

A membrane electrode assembly 20 includes an electrolyte membrane 22, anode catalyst layers 24a to 24d, and cathode catalyst layers 26a to 26d provided counter to the anode catalyst layers 24a to 24d, respectively. An insulating layer 60a is provided on the electrolyte membrane 22 between adjacent anode catalyst layers 24. An insulating layer 60b is provided on the electrolyte membrane 22 between adjacent cathode catalyst layers 26. A resistivity of the insulating layer 60 is preferably identical to or higher than that of the electrolyte membrane 22.