Provided is a tandem solar cell constituted for the purpose of hole block or electron block so that holes are not injected from a front subcell or electrons are not injected from a rear subcell into an intermediate layer arranged between subcells. A tandem solar cell comprises a pair of electrodes, at least two subcells, and intermediate layers each arranged between two adjoining subcells, wherein at least one intermediate layer has a hole block layer or an electron block layer. In particular, the hole block or electron block becomes more complete by setting the film thickness of the hole block layer or electron block layer equal to or greater than the maximum value of surface irregularities of a subcell immediately before formation of the block layer, and the performance as a tandem element is exhibited sufficiently.