  Low-energy dipole excitations in ${}^{10}$Be were investigated based on the
generator coordinate method with $\alpha + {}^6$He and $\alpha + \alpha + 2n$
cluster models. We obtained three $1^-$ states in $E_{x} < 15$~MeV, which show
different characters in the $E1$, compressive dipole, and toroidal dipole
transition strengths. We found the strong toroidal dipole transition in the
$1_1^-$ state, remarkable $E1$ strength in the $1^-_2$ state, and the strong
$E1$ and compressive dipole strength in the $1^-_3$ state. The $1^-_1$ is
described by the $\alpha + {}^6$He cluster structure, where as the $1^-_2$ and
$1^-_3$ states are understood by three-body excitations of the $\alpha + \alpha
+ 2n$ clustering.
