An acrylic composition, comprising long-chain di(meth)acrylate represented by Formula and mono(meth)acrylate; CH 2 =CR 1 -COO- -OCO-CR 1 =CH 2 [in the Formula, is a bivalent group having a number average molecular weight (Mn) of 500 or more and containing a repeating unit of a bivalent group formed by at least one diol selected from a polybutylene glycol in which the number of the repeating unit is 7 or more, ester diol and carbonate diol with two OH groups removed, and R 1 is H or CH 3], wherein a glass-transformation temperature (TgDMS) of a polymer of the acrylic composition determined by using the following method is 40°C or less, and the method for determining the glass-transformation temperature (TgDMS) comprises: adding 0.3 weight part of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator to 100 weight parts of the acrylic composition, and performing deaeration treatment at reduced pressure; injecting the acrylic composition into a mold comprising two glass plates disposed opposite to each other with an interval of 0.4 mm, and a gasket; irradiating the acrylic composition in the mold with an ultraviolet ray for 60 min at a peak intensity of 2.1 mW/cm 2 by using a chemical lamp to photopolymerize the acrylic composition and obtain a sheet-like material; obtaining a test piece having a thickness of 400 μm, a width of 6 mm, and a length of 50 mm from the sheet-like material; and determining the dynamic viscoelasticity of the test piece by using a dynamic viscoelasticity determination device (trade name: EXSTAR DMS6100, manufactured by SII Nano Technology (Inc.)), in a nitrogen atmosphere and under determination conditions of a frequency of 1 Hz, a temperature range of -50°C to 150°C, and a heating rate of 2°C/min, wherein a temperature of the maximum value as shown in a temperature-tanδ curve obtained from the results is the TgDMS, wherein the glass-transformation temperature (TgFOX) of the polymer of the mono(meth)acrylate calculated by using the following method is 90°C or less, and the method for calculating the glass-transformation temperature (TgFOX) comprises: calculating the glass-transformation temperature (TgFOX) of the polymer of the mono(meth)acrylate by the following Fox Equation using the glass-transformation temperatures of homopolymers of monomers that are recorded in "Polymer Handbook (1999 edition)" (John Wiley & Sons Inc.); 1 / Tg FOX = W 1 / Tg FOX 1 + W 2 / Tg FOX 2 +... + Wi / Tg FOXi [in the Mathematical Equation, i is the number of monomers that form mono(meth)acrylate, W1, W2,..., and Wi are weight factions of the monomers in mono(meth)acrylate, and TgFOX1, TgFOX2,..., and TgFOXi are the glass-transformation temperatures of homopolymers of the monomers]. adding 0.3 weight part of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator to 100 weight parts of the acrylic composition, and performing deaeration treatment at reduced pressure; injecting the acrylic composition into a mold comprising two glass plates disposed opposite to each other with an interval of 0.4 mm, and a gasket; irradiating the acrylic composition in the mold with an ultraviolet ray for 60 min at a peak intensity of 2.1 mW/cm 2 by using a chemical lamp to photopolymerize the acrylic composition and obtain a sheet-like material; obtaining a test piece having a thickness of 400 μm, a width of 6 mm, and a length of 50 mm from the sheet-like material; and determining the dynamic viscoelasticity of the test piece by using a dynamic viscoelasticity determination device (trade name: EXSTAR DMS6100, manufactured by SII Nano Technology (Inc.)), in a nitrogen atmosphere and under determination conditions of a frequency of 1 Hz, a temperature range of -50°C to 150°C, and a heating rate of 2°C/min, wherein a temperature of the maximum value as shown in a temperature-tanδ curve obtained from the results is the TgDMS, wherein the glass-transformation temperature (TgFOX) of the polymer of the mono(meth)acrylate calculated by using the following method is 90°C or less, and the method for calculating the glass-transformation temperature (TgFOX) comprises: calculating the glass-transformation temperature (TgFOX) of the polymer of the mono(meth)acrylate by the following Fox Equation using the glass-transformation temperatures of homopolymers of monomers that are recorded in "Polymer Handbook (1999 edition)" (John Wiley & Sons Inc.); 1 / Tg FOX = W 1 / Tg FOX 1 + W 2 / Tg FOX 2 +... + Wi / Tg FOXi [in the Mathematical Equation, i is the number of monomers that form mono(meth)acrylate, W1, W2,..., and Wi are weight factions of the monomers in mono(meth)acrylate, and TgFOX1, TgFOX2,..., and TgFOXi are the glass-transformation temperatures of homopolymers of the monomers].