Provided is a means for achieving an excellent plant growth promoting effect of a 5-aminolevulinic acid easily even with a few applications thereof. A solid fertilizer comprising the following components (A) and (B):(A) a 5-aminolevulinic acid represented by the following general formula (I): R2R1NCH2COCH2CH2COR3 (I)wherein R1 and R2 are each independently a hydrogen atom, an alkyl group, an acyl group, an alkoxycarbonyl group, an aryl group, or an aralkyl group； and R3 is a hydroxy group, an alkoxy group, an acyloxy group, an alkoxycarbonyloxy group, an aryloxy group, an aralkyloxy group or an amino group, a derivative thereof or a salt of the acid or the derivative, and(B) a solid fertilizer raw material.
