We discuss in detail the magnetic and thermal properties of a certain kind of plane decorated Ising lattice; that is, its interesting spin-ordering characteristics, such as the temperature and magnetic field dependence of the magnetization, the susceptibility and the heat capacity are investigated. These characteristics may be classified according to the ratio between two kinds of exchange coupling parameters. The system shows metamagnetism in certain cases. The characteristic magnetic field at which a logarithmic singularity takes place in the susceptibility as well as the heat capacity is obtained as a function of temperature. In some cases two characteristic fields are found below a certain temperature, above which only the one characteristic field survives up to a higher temperature. A number of typical curves which represent the relations of the magnetization, the magnetic susceptibility and the heat capacity with the magnetic field at a fixed temperature and with temperature at a fixed stregth of magnetic field are investigated.