  Corrections to scaling in the two-dimensional scalar phi^4 model are studied
based on non-perturbative analytical arguments and Monte Carlo (MC) simulation
data for different lattice sizes L (from 4 to 1536) and different values of the
phi^4 coupling constant lambda, i.~e., lambda = 0.1, 1, 10. According to our
analysis, amplitudes of the nontrivial correction terms with the
correction-to-scaling exponents omega_l < 1 become small when approaching the
Ising limit (lambda --> infinity), but such corrections generally exist in the
2D phi^4 model. Analytical arguments show the existence of corrections with the
exponent 3/4. The numerical analysis suggests that there exist also corrections
with the exponent 1/2 and, very likely, also corrections with the exponent
about 1/4, which are detectable at lambda = 0.1. The numerical tests clearly
show that the structure of corrections to scaling in the 2D phi^4 model differs
from the usually expected one in the 2D Ising model.
