The present invention relates to a catalyst for producing alkene using as a starting material alkane obtained by reducing an Mo—V—Te composite oxide having a crystal structure and being represented by formula (1): MoaVbTecOd  (1) wherein a is 1.0, b is from 0.01 to 1.0, c is from 0 to 1.0, and d is the number of oxygen atoms required to electrically neutralize the whole compound determined by the oxidation number of Mo, V and Te; a method for producing the same; and a method for producing alkenes from alkanes using the catalyst. The catalyst of the present invention enables improvement of the initial activity of the catalyst for producing alkene and selectivity of alkene.